Characterization of two 3-hydroxybutyrate dehydrogenases in poly(3-hydroxybutyrate)-degradable bacterium, Ralstonia pickettii T1

Two D-(-)-3-hydroxybutyrate (3HB) dehydrogenases, BDH1 and BDH2, were isolated and purified from a poly(3-hydroxybutyrate) (PHB)-degradable bacterium, Ralstonia pickettii T1. BDH1 activity increased in R. pickettii T1 cells grown on several organic acids as a carbon source but not on 3HB, whereas BDH2 activity markedly increased in the same cells grown on 3HB or PHB. To examine their biochemical properties, bdh1 and bdh2 were cloned and overexpressed in Escherichia coli, and their purified products were characterized. The kinetic parameters indicate that BDH1 is more suitable for converting acetoacetate to 3HB than BDH2, whereas BDH2 is more efficient for the reverse reaction than BDH1. Thus, R. pickettii T1 contains two BDHs with different biochemical properties and physiological roles: BDH1 for cell growth on organic acids other than 3HB and BDH2 for cell growth on 3HB or PHB.

Development of a commercial amperometric biosensor electrode for the ketone D-3-hydroxybutyrate

Representatives of the common classes of quinoid NADH redox mediator, including Meldola Blue (MB) 3, 4-methyl-1,2-benzoquinone (4-MBQ) 4, 1-methoxy phenazine methosulphate (1-MeO-PMS) 5 and 2,6-dichloroindophenol (DCIP) 6, are shown to inhibit the NAD-dependent enzyme D-3-hydroxybutyrate dehydrogenase (HBDH), severely limiting their utility in the construction of a stable biosensor electrode for the ketone body D-3-hydroxybutyrate (3-OHB). It is proposed that these mediators bind covalently to important thiol groups in the enzyme. This mode of inhibition is overcome through the use of mediators such as 1,10-phenanthroline quinone (1,10-PQ) 7, which avoid 1,4-nucleophilic addition with enzyme amino acid residues such as Cys. As a result, 1,10-PQ 7 was selected for incorporation in a biosensor electrode for 3-OHB. The resulting MediSense Optiumtrade mark beta-Ketone electrode is stable (<or=10% loss in response at 30 degrees C versus 4 degrees C) with a long shelf life of 18 months. Diabetics can determine their D-3-hydroxybutyrate level with good precision (0.43 mM 3-OHB, 10.5% CV; 1.08 mM, 5.9%; 3.55 mM, 3.2%; n=20 per level) and accuracy (versus reference assay: slope=0.98; intercept=0.02 mM, r=0.97, n=120) over the range 0.0-6.0 mM in 30 s using a small volume of blood (5 microl). The electrode has a low operating potential (+200 mV versus Ag/AgCl) such that the effect of electroactive agents in blood is minimised.

The content and distribution of troponin I, troponin T, myoglobin, and alpha-hydroxybutyric acid dehydrogenase in the human heart

We studied the content and distribution of heart-specific markers troponin I and troponin T in relation to conventional non-heart specific myoglobin and alpha-hydroxybutyric acid dehydrogenase (HBD) in the hearts of 34 patients who died of various causes. Tissue was obtained from the right and left ventricles, the interventricular septum, and the right and left atria. We found significant differences in the contents expressed per gram wet weight tissue in the right and left ventricles for troponin I (by 1 of the 2 methods used), troponin T, myoglobin, and HBD and no differences per gram of protein. The biochemical contents per gram wet weight tissue and per gram protein were significantly lower in the right and left atria for all studied markers compared with the right and left ventricles. No significant differences were found in biochemical contents between the right and left atria. These findings imply that estimation of myocardial damage through cardiac markers levels in serum depends on the site of injury (atrium or ventricle). Comparison of myocardial injury among individuals using marker levels in serum is not reliable because of the varied ranges of markers in tissue contents.

Three enzymes newly identified from the genus Eimeria and two more newly identified from E. maxima, leading to the discovery of some aliphatic acids with activity against coccidia of the domesticated fowl

Nine enzymes were detected in sporulated oocysts of Eimeria tenella and E. maxima, parasites of the domesticated fowl (Gallus gallus). Three enzymes, hydroxybutyrate dehydrogenase, alanine aminotransferase and gamma-glutamyltransferase, all identified for the first time in Eimeria of fowl, occurred both in E. tenella and in E. maxima. The remaining enzymes assayed had previously been found in various Eimeria species of fowl, although creatine kinase and glutamate dehydrogenase were hitherto unknown from E. maxima. The three enzymes newly recorded from Eimeria of fowl are of interest as potential genetic markers, and also as potential chemotherapeutic targets. The discovery of hydroxybutyrate dehydrogenase led to the demonstration of anticoccidial activity by some aliphatic acids. The paper also includes a list of the enzymes detected in Eimeria of fowl in previous studies.

Enantioselective depletion of mitochondrial glutathione concentrations by (S)- and (R)-3-hydroxy-4-pentenoate

(R,S)-3-Hydroxy-4-pentenoate rapidly and selectively depletes the mitochondrial glutathione pool in rat hepatocytes, but shows little cytotoxicity and does not induce mitochondrial dysfunction [Shan, X., et al. (1993) Chem. Res. Toxicol. 6, 75-81]. The objective of the present studies was to investigate the 3-hydroxybutanoate dehydrogenase-dependent oxidation of (R)- and (S)-3-hydroxy-4-pentenoate and the enantioselectivity of 3-hydroxy-4-pentenoate-induced depletion of mitochondrial glutathione concentrations in isolated rat liver mitochondria and hepatocytes. (S)-3-Hydroxy-4-pentenoate, but not (R)-3-hydroxy-4-pentenoate, was a substrate for 3-hydroxybutanoate dehydrogenase. Incubation of rat liver mitochondria or hepatocytes with (S)-3-hydroxy-4-pentenoate resulted in a time- and concentration-dependent depletion of mitochondrial glutathione concentrations, whereas (R)-3-hydroxy-4-pentenoate produced little depletion. These results show that (S)-3-hydroxy-4-pentenoate is a substrate for 3-hydroxy-butanoate dehydrogenase and is converted to the Michael acceptor 3-oxo-4-pentenoate, which reacts with glutathione and thereby depletes the mitochondrial glutathione pool. (S)-3-Hydroxy-4-pentenoate may find use in the study of mitochondrial glutathione homeostasis and the role of mitochondrial glutathione in cellular protection.

Identification and typing of pyogenic streptococci by enzyme electrophoretic polymorphism

Polyacrylamide-agarose gel electrophoresis was used to study polymorphism of lactate dehydrogenase (LDH), nucleoside phosphorylase (NSP), phosphoglucose isomerase (PGI), hydroxybutyrate dehydrogenase (HBD), adenylate kinase (ADK) and esterases of 44 strains of Streptococcus pyogenes, 25 group G streptococcal strains, 11 "S. equisimilis" strains, seven S. dysgalactiae strains, four S. canis strains, three S. equi strains and seven S. zooepidemicus strains. Analysis of LDH, NSP, PGI, HBD and ADK provided valuable interspecies differentiation, by showing that four groups of strains corresponded to the four known DNA homology groups. Esterases showed greater intraspecies variation than the other enzymes. The combined analysis of the six enzymes indicated 31 zymotypes among S. pyogenes, 14 in group G streptococci and 11 in "S. equisimilis" strains. This was shown to be an effective technique for typing pyogenic streptococci.

Combined enzyme histochemical and ultrastructural study on cryostat sections of pig heart to detect early reperfusion damage after ischaemia

In cardiac surgery, recognition of peroperative myocardial infarction may improve patient selection for prolonged circulatory support. The value of enzyme histochemistry to discriminate between reversible and irreversible myocardial damage at short periods of reperfusion was studied in an in vivo model of regional ischaemia in pig hearts. The left anterior descending coronary artery (LADCA) was clamped for 45 min followed by 2 h reperfusion (group 1, n = 3). Post-mortem heart tissue showed markedly decreased activities of lactate dehydrogenase (LDH) and beta-hydroxybutyrate dehydrogenase (BDH) as demonstrated in cryostat sections, accompanied by massive leakage of LDH in the venous effluent. The depleted areas showed irreversible cell damage based on the presence of flocculent densities in mitochondria. In group 2 (n = 6), LADCA flow was reduced to 40 per cent of the base-line value followed by 2 h reperfusion. Heart tissue showed normal LDH and BDH activities, except for some cells surrounding blood vessels, which activity was minimally decreased. Flocculent densities in mitochondria were never observed. We conclude that enzyme histochemistry of LDH and BDH activity on cryostat sections is a useful tool for detecting irreversible myocardial cell damage as early as 2 h reperfusion after ischaemia of the pig heart. The technique has potential applications in the detection of peroperative infarction in human biopsies.

Production and characterization of monoclonal antibodies to bovine brain succinic semialdehyde reductase

Monoclonal antibodies against bovine brain succinic semialdehyde reductase were produced and characterized. A total of nine monoclonal antibodies recognizing different epitopes of the enzyme were obtained, of which two inhibited the enzyme activity and three stained cytosol of rat spinal cord neurons as observed by indirect immunofluorescence microscopy. When unfractionated total proteins of bovine brain homogenate were separated by gel electrophoresis and immunoblotted, the antibodies specifically recognized a single protein band of 34 kDa, which comigrates with purified bovine succinic semialdehyde reductase. Using the antisuccinic semialdehyde reductase antibodies as probes, we investigated the cross-reactivities of brain succinic semialdehyde reductases from some mammalian and an avian species. The immunoreactive bands on western blots appeared to be the same in molecular mass--34 kDa--in all animal species tested, including humans. The result indicates that brain succinic semialdehyde reductase is distinct from other aldehyde reductases and that mammalian brains contain only one succinic semialdehyde reductase. Moreover, the enzymes among the species are immunologically very similar, although some properties of the enzymes reported previously were different from one another.

[Aspects of the enzymatic evaluation in Plasmodium falciparum malaria infection]

To try to find effects of malaria on clinical serum activity of certain enzymes, 3 groups of infants--malarial, asymptomatic carrier and normal controls--have been designed. Parasitologic data have been compared with serum concentration of lactate dehydrogenase (LDH), Hydroxybutyrate dehydrogenase (HBDH) alanine aminotransferase (ALT), gamma glutamyl transferase (GGT) and 5'nucleotidase (5'Nu). Results show that only LDH and HBDH are significantly increased. Respective coefficients of correlation r = 0.32 (p < 0.05) and r = 0.39 (p < 0.01) show that increasing in LDH and HBDH are linked to malarial parasite density. LDH and HBDH increasing might therefore constitute a marker of malaria.

Comparison of magnetic resonance imaging studies with enzymatic indexes of myocardial necrosis for quantification of myocardial infarct size

To evaluate the potential of gadolinium-diethylene triamine pentaacetic acid (DTPA)-enhanced magnetic resonance imaging (MRI) in the quantification of infarct size in patients with a first acute myocardial infarction, 24 patients with a first acute myocardial infarction were studied by electrocardiographic gated MRI at a mean of 4.3 days after the acute event. Multislice, single-phase, T1-weighted, spin-echo MRI in the true short-axis plane was performed 20 minutes after intravenous injection of gadolinium-DTPA (0.15 mmol/kg of body weight). Circumscript myocardial regions of increased signal intensity on gadolinium-DTPA-enhanced images were considered to be infarcted. Infarct size (in g) was determined using Simpson's rule, and was compared with that based on cumulative release of alpha-hydroxybutyrate dehydrogenase activity in plasma and with peak creatine kinase-MB level in plasma. Infarct size quantified with MRI correlated well with "enzymatic" infarct size (in g equivalents) (y = 0.99 x + 0.71; r = 0.93; p = 0.0001) and peak creatine kinase-MB levels (r = 0.72; p = 0.002). It is concluded that gadolinium-DTPA-enhanced MRI enables accurate quantification of infarct size in patients with a first acute myocardial infarction.

Distribution of 3-hydroxybutyrate dehydrogenase in primary lobules of rat liver

In an attempt to establish the functional organization of the hepatic parenchymal unit, we used histo- and microchemical procedures to assess metabolic liver cell heterogeneity at the level of the primary lobule. Because of the close interrelation of glucogenesis and ketone body formation, and in view of the distinct regional differences of the in vivo activity of glucose-6-phosphatase (G6Pase), these techniques were used on livers from male rats to investigate the distribution of the ketogenic enzyme, 3-hydroxybutyrate dehydrogenase (3-HBDH), during the post-resorptive phase. A close reciprocity was found between the general increase in the activity of 3-HBDH and the decrease of the in vivo activity of G6Pase along the sinusoidal axis, and also with regard to enzyme gradients along sinusoids of different origin. The activity of the ketogenic enzyme was higher throughout septal than portal sinusoids, whereas the opposite applied to the glucogenic enzyme. Histo- and microchemical data support the concept of a lobular parenchymal unit composed of "primary lobules," and show also that hepatocyte function varies with cell location along the sinusoidal axis and with the origin of the sinusoids.

[Disorders of myocardial metabolism in sudden coronary death in the presence of coronary atherosclerosis: findings of quantitative histoenzymologic studies]

The activity of human myocardial enzymes in sudden coronary death (SCD) was quantitatively histochemically examined. The activity of succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), beta-oxybutyrate dehydrogenase (beta-OBDH), alpha-glycerolphosphate dehydrogenase (alpha-GPDH), NAD-diaphorase (NAD-ase), and glucose-6-phosphate dehydrogenase (G-6-PDH) was measured on prompt autopsies (up to 3 hours of death onset). beta-OBDH and LDH showed an increase in activity in the myocardium from the subjects who had suddenly died from coronary heart disease without evident changes in the heart. In SCD in the presence of small cardiosclerosis, the activity of the enzymes characterizing the major processes of energy generation was also enhanced, which was caused by moderately severe myocardial hypertrophy. In the myocardium from the subjects who had died from coronary heart disease in the presence of large postinfarction cardiosclerosis, the activity of the enzymes was directly related to the degree of myocardial hypertrophy and the signs of chronic heart failure. As myocardial hypertrophy progressed, the enzymatic activity rose, but there were signs of chronic heart failure, it fell. The findings suggest that the changes in myocardial enzymatic activity in SCD are heterogeneous and associated with the type of prior abnormalities in the cardiovascular system.

A sensitive radioisotopic method for the measurement of NAD(P)H: its application to the assay of metabolites and enzymatic activities

A radioisotopic method for the assay of NADH or NADPH is presented, which is based on the conversion of 2-[U-14C]ketoglutarate to 14C-labeled glutamate in the reaction catalyzed by glutamate dehydrogenase. The efficiency of the method is close to 75%, its precision (coefficient of variation) close to 5%, and its sensitivity close to 0.1 pmol/sample. This simple and rapid method can be applied to the measurement of several metabolites and enzymatic activities. In the present study, its application to the assay of sorbitol, 3-hydroxybutyrate, glutamate dehydrogenase, 3-hydroxybutyrate dehydrogenase, and glyceraldehyde-3-phosphate dehydrogenase is documented.

Developmental regulation of D-beta-hydroxybutyrate dehydrogenase in rat liver and brain

The activities of ketone-metabolizing enzymes in rat brain increase 3- to 5-fold during the suckling period before decreasing to the adult level after weaning. We have observed that a similar developmental pattern also exists for D-beta-hydroxybutyrate dehydrogenase (BDH) in rat liver. Utilizing antibodies prepared against the purified protein we determined that the changes in BDH activities in both brain and liver are due to changes in the amount of BDH in the mitochondria. In vitro translations of isolated RNA followed by immunoprecipitation revealed that the increase in BDH activity and content was correlated with an increase in the level of functional BDH-mRNA in both liver and brain.

Regulation of D-beta-hydroxybutyrate dehydrogenase in rat hepatoma cell lines

Quantitation of D-beta-hydroxybutyrate dehydrogenase (BDH) in normal rat hepatocytes was compared with that in two rat hepatoma cell lines, H4-II-EC3 and RLT-3C. BDH activity in normal rat hepatocyte mitochondria was 321 nmol/min/mg, which was greatly reduced to 10.7 nmol/min/mg and 1.7 nmol/min/mg in H4-II-EC3 and RLT-3C cell mitochondria, respectively. The cell growth rate and L-[35S]methionine incorporation rate showed that RLT-3C cells had the highest growth rate (32.4-h doubling time) and the fastest protein biosynthesis rate (2.65 x 10(5) cpm/min/10(6) cells). The H4-II-EC3 cell line grew more slowly (48.5-h doubling time) and had lower protein biosynthesis rate (1.46 x 10(5) cpm/min/10(6) cells). The protein synthesis rate in hepatocytes was 1.25 x 10(5) cpm/min/10(6) cells. These results suggest that there is a reciprocal correlation between BDH activity and cell growth and protein synthesis rates. Immunochemical quantitation of BDH showed the amount of BDH in H4-II-EC3 and RLT-3C cells was about 4.8 and 0.5% of that in normal rat hepatocytes, respectively. Quantitation of BDH by biosynthesis indicated that BDH content in H4-II-EC3 cells and RLT-3C cells was 9.3 and 4.0% of that of normal hepatocytes, respectively. Precursor BDH synthesized by in vitro translation primed with RNA of H4-II-EC3 cells or RLT-3C cells was 3.0 and 1.1% of that translated from normal rat hepatocyte RNA. These results suggest that the decrease in BDH content in hepatoma cells results from a decrease in functional BDH-mRNA. The coupling of a decrease in BDH activity with an increase in activity of succinyl-CoA: acetoacetyl-CoA transferase in hepatoma cells may play a role in generating additional energy required for the rapid growth of tumor cells.

Evaluation of eosin-fluorescence in the diagnosis of sudden cardiac death

The diagnostic significance of the eosin-fluorescence method was evaluated and compared with the enzymehistochemical beta-hydroxybutyrate-dehydrogenase method (beta-HBDH) and the degree of hyperchromasia in 568 samples from 24 bets-HBDH-negative and beta-HBDH-positive sudden cardiac deaths (SCD) and 23 non-cardiac deaths as controls. The effect of autolysis was investigated separately on isolated human hearts at +4 degrees C and +22 degrees C. All samples were examined without any knowledge of clinical or autopsy data. Normal olive-green fluorescence was observed in only five individuals of the control group and two in the beta-HBDH-negative one. The frequency of the yellow-fluorescence and hyperchromasia increased from the control subjects towards the beta-HBDH-positive-ones. The difference in frequency distribution of fluorescence between the groups was statistically highly significant (P less than 0.001). The change in fluorescence did not correlate with the loss of beta-HBDH-reaction or the distribution pattern of hyperchromasia. Postmortem autolysis did not change the fluorescence significantly but the 78% wrong positive subjects in the control group render this method too sensitive and unreliable for medicolegal purposes.

Myocardial enzyme depletion in infarcted human hearts: infarct size and equivalent tissue mass

Myocardial activities of several enzymes were measured in infarcted and non-infarcted areas of heart sections obtained from eight patients who died after acute myocardial infarction. Similar data were obtained from four patients with cardiovascular disorders who died from causes other than myocardial infarction and from six patients without previously known heart disease. It was found that both non-infarcted and infarcted tissue samples contained considerably altered enzyme activities. This finding explains the low correlations between enzymatic and histological estimates of infarct size previously reported. However, when the residual myocardial activities of different enzymes were compared with each other, a close correlation was found between creatine kinase, alpha-hydroxybutyrate dehydrogenase, and aspartate aminotransferase. It appears that the pathological changes in the myocardial activities of these enzymes may be explained by the phenomenon of diluted myocardium. This indicates that myocardial injury, as estimated from plasma enzyme activities, may still be expressed meaningfully in gram equivalents of healthy myocardium.

Comparison of 3-hydroxybutyrate dehydrogenase from bovine heart and rat liver mitochondria

3-Hydroxybutyrate dehydrogenase is a lipid-requiring enzyme with an absolute requirement of phosphatidylcholine for enzymatic activity. Purification of the enzyme to homogeneity from bovine heart mitochondria was described more than a decade ago [H. G. Bock and S. Fleischer (1975) J. Biol. Chem. 250, 5774-5781]. We have modified the purification procedure so that it is faster, the yield has been improved, and the specific activity is greater by approximately 50%. The updated procedure has also been applied to isolate the enzyme from rat liver mitochondria. Characteristics of the enzyme from bovine heart and rat liver mitochondria have been compared and found to be similar with respect to: (1) purification characteristics; (2) amino acid composition; (3) pH optimum for enzymatic activity; (4) kinetic characteristics; (5) molecular weight as determined by sedimentation equilibrium in guanidine hydrochloride; (6) peptide maps; (7) immunological cross-reactivity. These studies show that 3-hydroxybutyrate dehydrogenase from bovine heart and rat liver mitochondria, though similar, are not identical.

Ethanol alters microvasculature enzymes in the rat forebrain

Forebrain arterioles were analyzed histochemically to determine the effects of an acute administration of ethanol on key enzymes of aerobic and anaerobic metabolism as well as on the hexose monophosphate shunt in rats. The enzymes were glucose 6-phosphate dehydrogenase, cytochrome oxidase, lactate dehydrogenase, beta-hydroxybutyrate dehydrogenase, and isocitrate dehydrogenase. All enzymes were quantified under two conditions: 1 h and 2 days after ethanol administration. Significant changes were noted in four of the five enzymes measured after 1 h and in all five enzymes when measured 2 days after ethanol administration. Our data suggest that ethanol may cause impaired metabolism in the forebrain microvasculature, which, in turn, may account for some of the characteristic behavioral effects of acute ethanol administration.

Effect of diabetes, adrenalectomy and hypophysectomy on D-3-hydroxybutyrate dehydrogenase activity and substrate oxidation by rat mitochondria

In good agreement with previous observations, D-3-hydroxybutyrate dehydrogenase (OHBD) activity in disrupted liver mitochondria decreased significantly in chronic diabetic rats, whereas insulin treatment prevented this decrease. Similar effects were observed with kidney mitochondria. Adrenalectomy increased OHBD activity in liver and brain mitochondria from normal rats and in liver mitochondria from diabetic rats. Corticosterone depressed OHBD activity in liver mitochondria of normal rats and restored the normal level of OHBD in adrenalectomized rats. Hypophysectomy increased OHBD activity in normal rats, this effect being further increased by growth hormone administration. D-3-hydroxybutyrate (OHB) oxidation by liver mitochondria from diabetic, adrenalectomized or hypophysectomized rats varied as expected from OHBD activity in disrupted mitochondria, but to a relatively lesser degree. Submitochondrial particles from diabetic rats showed significant diminution in OHB-, succinate- and NADH-oxidase activities, whereas mitochondria from diabetic rats oxidized succinate and L-malate + L-glutamate at a slower rate than the corresponding controls.

Zonal analysis of metabolic profiles of articular-epiphyseal cartilage chondrocytes: a histochemical study

Articular-epiphyseal cartilage from the femur of New Zealand rabbits was subjected to histochemistry for determination of the presence of metabolic enzymes along its zonal stratification. Glycolytic enzymes were strongly reactive in all of the zones. Krebs cycle enzymes, enzymes of the hexose monophosphate shunt and the respiratory chain enzymes showed a progressive increase in reactivity from the tangential zone through the top half of the epiphyseal zone. Indicators of lipid metabolism were fairly high in all regions of the cartilage.

Kinetic aspects of the role of phospholipids in D-beta-hydroxybutyrate dehydrogenase activity

Interactions of phospholipids with D-beta-hydroxybutyrate dehydrogenase (BDH), a lecithin-requiring enzyme, have been studied by a kinetic approach. The process of reactivation of BDH by phospholipids, which follows a second-order mechanism, reveals that (1) at least 2 mol of lecithins is essential for the reactivation of the enzyme, and (2) the enzyme contains two dependent binding sites for lecithins. The graphic representation of the time course of reactivation shows a latent phase which decreases when there is an increase in the amount of phospholipids. A Scatchard plot treatment of the reactivation kinetic data reveals the presence of two classes of phospholipid binding sites, which exhibit high and low affinities related to the binding of four and two lecithin molecules, respectively. The effect of temperature on BDH activity and on the inactivation of the apoenzyme with N,N'-dicyclohexylcarbodiimide (a specific carboxyl reagent) or with phenylglyoxal (a specific arginine reagent) shows a break at 22-24 degrees C, indicating a slight structural change in the enzyme-active site around this temperature. In addition, the variations in enzyme kinetic parameters, according to the nature of phospholipids, are in agreement with conformational changes related to the nature and to the fluidity state of phospholipids. However, the apparent NAD+ binding constant does not depend on the phospholipid's fluidity.

Involvement of tyrosyl residues in the structure-function relationships of D-beta-hydroxybutyrate dehydrogenase: a phospholipid-requiring enzyme

The involvement of tyrosyl residues in the function of D-beta-hydroxybutyrate dehydrogenase, a lipid-requiring enzyme, has been investigated by using several tyrosyl modifying reagents, i.e., N-acetylimidazole, a hydrophilic reagent, and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole and tetranitromethane, two hydrophobic reagents. Modification of the tyrosyl residues highly inactivates the derived enzyme: Treatment of the enzyme with 7-chloro-4-nitro[14C]benzo-2-oxa-1,3-diazole leads to an absorbance at 380 nm and to an incorporation of about 1 mol of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole per polypeptide chain for complete inactivation. Inactivation by N-acetylimidazole induces a decrease in absorbance at 280 nm which can be reversed by hydroxylamine treatment. On the other hand, the ligands of the active site, such as methylmalonate, a pseudosubstrate, and NAD+ (or NADH), do not protect the enzyme against inactivation. In contrast, the presence of phospholipids strongly protects the enzyme against hydrophobic reagents. Finally, previous modification of the enzyme with N-acetylimidazole does not affect the incorporation of 7-chloro-4-nitro[14C]benzo-2-oxa-1,3-diazole while modification with tetranitromethane does. These results indicate the existence of two classes of tyrosyl residues which are essential for enzymatic activity, and demonstrate their location outside of the active site. One of these residues appears to be located close to the enzyme-phospholipid interacting sites. These essential residues may also be essential for maintenance of the correct active conformation.

Isoenzyme analyses of Malaysian Schistosoma, S. mekongi and S. japonicum by isoelectric focusing in polyacrylamide gel

Isoenzyme patterns of adult Malaysian Schistosoma, S. mekongi and S. japonicum strains were analysed by isoelectric focusing (IEF) in polyacrylamide gel. Enzyme patterns obtained from Malaysian Schistosoma homogenates differed from those of S. mekongi and S. japonicum strains. Malaysian Schistosoma was found to differ from S. japonicum by 8 enzymes, namely phosphoglucomutase, phosphoglucoisomerase, malate dehydrogenase, acid phosphatase, hydroxy-butyrate dehydrogenase, hexokinase and alkaline phosphatase, and from S. mekongi by phosphoglucomutase, malate dehydrogenase, aldolase and alkaline phosphatase. These results and the distinct biology of the parasite suggest that Malaysian Schistosoma is a new species in the S. japonicum complex.

Bioluminescence procedures for the measurement of NAD(P) dependent enzyme catalytic activities in submicrogram quantities of rabbit and human nephron structures

Reduced flavin mononucleotide dependent luciferase (EC 1.14.14.3) from Photobacterium fischeri has been used to measure NAD(P) dependent enzymes in submicrogram quantities of tissue homogenates and isolated structures of rabbit and human kidney. The procedure for measuring NAD(P)H was optimized, with internal standardization, to give a linear constant signal between 1 and 100 pmol. This method was applied to the measurement of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) along the various structures of the rabbit nephron, microdissected from fresh tissue slices. Blank and recovery measurements were performed on each structure, and enzyme catalytic activities were calculated on the basis of tubular length and protein. Glucose-6-phosphate dehydrogenase was found to be present in all nephron structures with highest catalytic activities in glomeruli, thin limbs of Henle's loop and medullary collecting tubules. Lowest catalytic activities were detected in the pars recta of proximal tubules, the distal convoluted and the connecting tubule. The mitochondrial 3-hydroxybutyrate dehydrogenase exhibited a different distribution pattern: Highest catalytic activities were found in the cortical ascending limbs of Henle's loop, the proximal and distal convoluted tubule. An unusual internephron heterogeneity for this enzyme was found in the distal convoluted tubule. Catalytic activities in thin limbs of Henle's loop, the medullary ascending limb, and the cortical and medullary collecting tubule were not significantly different from blank activities. The results obtained in isolated nephron segments agreed with those calculated from cortex and medullary homogenates. In a preliminary experiment on human kidney it could be demonstrated that the procedures can be applied to fresh human biopsy samples. The bioluminescence method offers several advantages (simplicity, rapidity) in comparison with the classical techniques used for ultramicro analysis of tissue enzymes (enzymatic cycling, radiochemical tests). The results confirm the biochemical heterogeneity of nephron structures and allow conclusions about species dependent functional differences of the pentose-phosphate cycle and renal ketone body metabolism along the nephron.

Metabolic blocker-induced cell damage in rat cardiac tissue. Comparison of three models currently used: the isolated perfused heart, heart cell cultures and isolated myocytes

In a comparative study on metabolic blockade-induced cardiac cell damage, three different heart (cell) preparations are exposed to potassium cyanide (KCN) and iodoacetamide (IAA) in fixed concentrations (5 and 0.1 mmol/l, respectively). The preparations used are the perfused rat heart, isolated rat heart myocytes and rat heart cell cultures. Irreversible heart cell damage is reflected by the release of a cytoplasmic enzyme, LDH (lactate dehydrogenase), or HBDH (alpha-hydroxybutyrate dehydrogenase) from the heart (cell) preparations. Metabolic blockade-induced release of 50% of the originally intracellularly located LDH or HBDH is reached after 2-3 h from rat heart cell cultures, after 2-4 h from isolated rat heart myocytes and after variable (coronary flow-dependent) durations of perfusion from perfused rat hearts. It is concluded that to study the effect of toxic agents on myocytic integrity, the use of isolated cardiac myocytes and heart cell cultures is preferable to the use of isolated perfused hearts.

Circulating glucose, insulin and ketone bodies and enzymes of ketone body utilization in brain mitochondria from suckling rats treated with high L-thyroxine doses

The neo-T4 syndrome was induced by subcutaneous administration of a total dose of (150 micrograms) L-thyroxine (T4) to rats from their first day of live. Neo-T4 animals and their controls were sacrificed at 2, 4, 8, 11, 14, 22 and 25 days of age. A decrease in body weight was observed from the second day of life, and a decrease in brain weight from the eighth day of life in the neo-T4 animals. Blood glucose and plasma insulin levels were decreased from 2nd day through 22nd day of life. Total plasma ketone bodies and beta-OH butyrate levels increased in the neo-T4 animals with respect to controls. until 8th day, although acetoacetate increased only until 4th day. The activity of key enzymes in the ketone bodies utilization pathway (3-hydroxybutyrate dehydrogenase, 3-oxoacid CoA-transferase and acetoacetyl-CoA thiolase) were also measured in the animals brain. We found an activation of 3-hydroxybutyrate dehydrogenase until 11th day and 3-oxoacid CoA-transferase until 14th day, but no change in acetoacetyl CoA-thiolase was observed. Ketone bodies play a key role as energy substrates and precursors of brain lipids during the period of intense growth and myelination of the CNS. Considering the alterations described in this paper it seems that neo-T4 syndrome could be an interesting model for studying metabolism of those substances in brain.

Single-step bioluminescence analyses of enzymes, using Cibacrone Blue chromatography for removal of interfering dehydrogenases

To provide for bioluminescence measurements of the enzymatic activities of dehydrogenases, disturbing contaminants were removed from a bacterial luciferase extract by chromatography, using Blue Sepharose CL-6B, a cross-linked agarose to which Cibacrone Blue F3G-A is covalently attached. This compound has a strong affinity to the dinucleotide fold, which is a region in enzymes binding NAD(H) or NADP(H). In contrast to the absorbed dehydrogenases, both luciferase and oxidoreductase were easily eluted and appeared close to the main bulk of UV-absorbing but analytically less important material. A rapid recording of the elution of luciferase was accomplished with a new electrochemical bioluminescence assay. Due to this and the early elution of the desired material, it could be chromatographed, recognized and collected in less than two hours. Thereby the light-yielding capacity of the sensitive material was well preserved. For bioluminescence assay solutions composed of pooled oxidoreductase-luciferase fractions, FMN and a long chain aldehyde were prepared and supplemented with NAD+ and either lactate, malate or 3-hydroxybutyrate. The analyses were carried out in a single step performance by adding the enzyme sample to the luciferase solution. Minute amounts of lactate dehydrogenase, malate dehydrogenase and 3-hydroxybutyrate dehydrogenase yielded a linear light response permitting assay in the lower part of the femtomole region. In case a dehydrogenase does not occur as a contaminant of a commercial luciferase preparation, purification with Cibacrone Blue can be omitted as demonstrated for glucose-6-phosphate dehydrogenase.(ABSTRACT TRUNCATED AT 250 WORDS)

Histochemical patterns of succinic semialdehyde dehydrogenase activity within the Purkinje cell population during rat cerebellar histogenesis

The histochemical detection of SSADH activity corroborates some crucial steps of the maturation of Purkinje neurons in rat cerebellum. The SSADH-specific activity seems to appear early, within the first week of postnatal life, in a few Purkinje cells. Around the 12th day most cells were SSADH positive, even if some were still negative. This period is an important step of postnatal histogenesis when many histological and physiological data show important neuronal changes. At the end of cerebellar histogenesis the SSADH activity showed the same pattern as in adult rats. Our findings suggest that in the Purkinje cell population the maturation does not occur simultaneously thus confirming the concept of "heterogeneity" (different functional states).

The measurement of enzyme activities in endomyocardial biopsies from patients with congestive (dilated) cardiomyopathy and specific heart muscle disease

50 patients with heart muscle disease have been investigated using routine invasive and non-invasive techniques, including endomyocardial biopsy. Enzyme activities in myocardial tissue obtained by biopsy have been measured in dilated cardiomyopathy and heart muscle disease and compared. Significant differences in enzyme activity have been found between dilated cardiomyopathy and alcoholic heart muscle disease when the groups are defined by detailed drinking histories. CPK (p less than 0.002), MDH (p less than 0.001), LDH (p less than 0.001) and alpha HBD (p less than 0.001). The changes in the enzyme levels may be an adaptive response to alcohol although serial study did not show a fall in enzyme activities after 3-6 months abstinence. Preliminary data furthermore indicates an association of the alpha HBD/LDH and LDH/CPK enzyme activity ratios and ejection fraction. This data supports the diagnosis of a specific heart muscle disease in response to alcohol excess.

LSH-X and HBDH/LDH ratio in human semen

The enzymatic activities of lactate dehydrogenase (LDH) and alpha-hydroxybutyrate dehdyrogenase (HBDH) were measured in 87 semen samples. The highest values of these enzymes correspond to the specimens with greatest sperm density and motility. There was a positive correlation between the enzymatic parameters and sperm density and motility. There was a positive correlation between the HBDH/LDH ratio and the percent LDH-X. The estimation of the HBDH/LDH ratio, easily and rapidly done, can be a substitute for direct LDH-X estimations. The HBDH/LDH ratio greater than 1.0 that was noted in men with good sperm motility and normal sperm counts, could represent a reliable index of semen quality.

Enzyme levels in semen of men with different types of azoospermia

The levels of eight enzymes have been measured in the semen of 15 azoospermic subjects. The results indicate that the values of the enzymes Creatine kinase, and Alanine aminotransferase, just as the Aspartate aminotransferase/Alanine aminotransferase ratio are significantly different between excretory and secretory azoospermics. The enzymes Aspartate aminotransferase, Lactate dehydrogenase, alpha-Hydroxybutyrate dehydrogenase, Gammaglutamyl transferase, Acid phosphatase, and Alkaline phosphatase and the alpha-Hydroxybutyrate dehydrogenase/Lactate dehydrogenase ratio have values which do not differ significantly between the two groups of azoospermic men.

Enzyme studies and neonatal brain damage

The authors report a double-blind study of 57 full-term newborn infants prospectively subjected to clinical, electroencephalographical, blood and cerebrospinal fluid, and developmental examinations. Four enzymatic activities were measured in blood and CSF: aminotransferase (ASAT), creatine kinase (CK), lactate dehydrogenase (LD) and hydroxybutyrate dehydrogenase (HBD). Close relationships of enzymatic levels with psychomotor outcome are reported. In blood, ASAT and CL seemed to be the most important determinations, allowing threshold-values to be suggested. In CSF, LD and HBD were the determinations the most closely related to psychomotor events at age one. This method seems to be of theoretical as well as practical importance in evaluating neonatal brain injury.

The (iso)enzyme activities of lactate dehydrogenase, alpha-hydroxybutyrate dehydrogenase, creatine kinase and aspartate aminotransferase in human myocardial biopsies and autopsies

In a study on enzyme activities in normal human myocardial tissue the activities of lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (HBDH), creatine kinase (CK), and aspartate aminotransferase (AST), and the activities of the isoenzymes of LDH (1--5) and AST (c and m) were measured in myocardial specimens obtained from live patients (18 biopsies) and postmortem (14 autopsies). Comparison of measurements in 4 right ventricular biopsies from 1 patient with those in 9 right ventricular biopsies from 9 patients shows that (1) the enzymes studied are homogeneously distributed throughout the right ventricular myocardium, (2) errors in the measurement of the activities of the enzymes studied are within 5%, and (3) inter-individual differences in myocardial enzyme activities are quite considerable (10--17%). No significant differences in the activities of the enzymes studied were found between left and right ventricular myocardium. The effect of autolysis on the activities of the enzymes studied in myocardial specimens obtained postmortem is small, amounting to -1% to -6% in the first 10 h, irrespective of whether a linear or an exponential decay of enzyme activity is assumed. Comparison of myocardial enzyme activities in biopsies with those in autopsies, the latter being corrected for autolysis-induced inactivation, reveals significant differences with respect to CK, AST and mAST. At present it is impossible to conclude whether these differences were due to the different conditions existing before the myocardial specimens were frozen at -20 degrees C or to the different types of pathology present in the hearts from which the specimens were taken.

Time-course of mitochondrial and cytoplasmic oxidoreduction state of rat liver following an intravenous glucose load

Changes in mitochondrial and cytoplasmic oxidoreduction states after an intravenous glucose infusion were studied in the freeze-clamped liver of normal and alloxan-induced diabetic rats. In normal rats the mitochondrial oxidoreduction state (NAD+/NADH) increased maximally at 5 min after glucose infusion (p less than 0.001) and then returned to about normal fasting level at 30 min later. The cytoplasmic oxidoreduction state reached its peak level at 30 min after glucose infusion (p less than 0.001). A clear temporal correlation was observed between the mitochondrial oxidoreduction state and insulin and glucose levels in plasm. On the other hand, in alloxan-induced diabetic rats no changes were detected in the oxidoreduction state os either mitochondria or cytoplasm in response to glucose infusion. Therefore the increase in portal insulin level as it occurs in response to the rise of blood glucose may play a role in the shift of the mitochondrial oxidoreduction state to its more oxidized state. This shift seems likely to be due to an accelerated removal of the reducing equivalents through electron transfer by the respiratory chain.

Starch gel electrophoresis: an effective method for separation of pathogenic and nonpathogenic Naegleria strains

Isoenzyme electrophoresis of 7 different enzyme systems was used to compare 24 strains of Naegleria fowleri and 6 strains of N. gruberi. The 30 strains could be grouped into 4 distinct categories based upon zymogram patterns. No interstrain band variation in all enzyme systems was demonstrated in pathogenic strains of N. fowleri. Three nonpathogenic high temperature-tolerant strains of Naegleria had similar zymograms. Four of the 5 remaining nonpathogenic Naegleria strains had no interstrain band variation. Based upon zymograms, the 22 pathogenic strains constitute a homogenous species. Similarly the high temperature-tolerant nonpathogenic strains formed a cohesive group. The remaining nonpathogenic strains could be separated into 2 groups.

Measurement of HBDH, CK and gamma-GT activities and comparison of the precision of four instruments used in kinetic analyses

A comparative analysis of low, normal and high activity of HBDH, CK, and gamma-GT was made using different kinetic measurement principles. The data revealed that the two-step integration technique and multi-point measurements evaluated by computer are essentially more accurate than the traditionally applied 3 x 1 minute enzyme determination.

Enzyme analyses of Bulinus africanus group snails (Mollusca: Planorbidae) from Tanzania

38 population samples of snails of the Bulinus africanus group, collected from three separate areas of Tanzania, have been examined. Enzymes in crude digestive gland extracts of individual snails have been analysed by isoelectric focusing in polyacrylamide gels. The enzymes studied were: malate dehydrogenase (MDH); phosphoglucomutase (PGM); glucosephosphate isomerase (GPI); acid phosphatase (AcP) and hydroxybutyrate dehydrogenase (HBDH). Samples of B. nasutus were clearly differentiated from other species and enzyme differences were apparent between samples from the lake and coastal areas. Similarly, although clear distinctions could not always be made, samples of B. africanus, B. globosus and B. ugandae were characterized by their enzyme types. Individual variation was detected within populations and the significance of enzyme polymorphisms in relation to identification has been considered. No correlation was found between snail enzyme type and susceptibility to Schistosoma haematobium or S. bovis.

Occurrence and possible adaptive significance of some histochemically demonstrable dehydrogenases in two entosymbiotic rhabdocoels (Platyhelminthes: Turbellaria)

1. The occurrence and distribution of twelve dehydrogenases have been studied histochemically in two species of rhabdocoel turbellarians entosymbiotic in marine bivalves. 2. Both species (Paravortex scrobiculariae in Scrobicularia plana and P. cardii in Cerastoderma edule) possess dehydrogenases concerned with the three major energy-producing pathways. 3. P. scrobiculariae shows a much greater emphasis on glycolysis than does P. cardii. 4. It is suggested that the emphasis on glycolysis in P. scrobiculariae is an adaptation to regular variations in oxygen supply in its habitat; this adaptation facilitates feeding and associated migrations within the host which occur at times when the host is not submerged by the tide and when oxygen is likely to be in short supply. 5. Dehydrogenases associated with the pentose phosphate shunt are especially evident in the developing embryos of both species and are probably concerned with synthesis of nucleotides and nucleoproteins.

A comparative histochemical study of the masseter muscle of the cattle, sheep, swine, dog, guinea pig, and rat

The masseter muscles of different mammals were studied by means of hisotchemical reactions: NADH: Nitro BT oxidoreductase (NADHOX), 3-hydroxybutyrate: NAD+ oxidoreductase (HBOX), glycerol-3-phosphate: menadione oxidoreductase (GPOX), and acid-stable and alkali-stable myosin adenosine triphosphatase (ATPase). The masseter mucles of cattle and sheep consisted only of the fibres that reacted moderately for GPOX and strongly for NADHOX, HBOX, and the acid-stable ATPase. The masseter fibres of rats and guinea pigs reacted uniformly and strongly for GPOX and the alkali-stable ATPase. The fibres of the rats showed a weak to strong reaction for NADHOX and mostly a negative reaction for HBOX, whereas those of the guinea pigs reacted uniformly and strongly for NADHOX and HBOX.The masseter fibres of swine and dogs showed a weak or strong reaction for the alkali-stable and a negative or weak reation for HBOX. The fibres of the swine were weak to strong in NADHOX activity and those of the dogs uniformly strong; the fibres of the two species gave a moderate to strong reaction for GPOX. The masseter fibres of the ruminant differed from those of the other species in histochemical properties, and appeared to have the histochemical characteristics that meed functional demands for slow, long-term exercise.

Lactate dehydrogenase (LD), hydroxybutyrate dehydrogenase (HBD), and LD-isoenzymes in brain tissue

The total activities of lactate dehydrogenase (LD) and hydroxybutyrate dehydrogenase (HBD), and the LD isoenzyme distribution were determined in tissue samples taken in vivo from different parts of the rabbit brain, and in cortical grey, subcortical white, and cerebellar tissue from man. The total LD and HBD activities were found to be higher in the brain stem than in the cerebral hemisphere, basal ganglia, and cerebellum of the rabbit brain. The isoenzyme distribution in the brain stem and the cerebellum showed an anodal shift, i.e., significantly higher activities of LD1 compared with the cerebral hemisphere and the basal ganglia. In man the total LD activity was found to be lower in white than in grey matter, although the isoenzyme patterns did not differ. The implications of these findings in relation to the LD isoenzyme pattern in serum after traumatic brain injury are discussed.

Determination of isoenzyme contents of lactic dehydrogenase activity and 2-hydroxybutyric dehydrogenase activity in lactic dehydrogenase preparations

In this inestigation, a determination of the isoenzyme contents of LDH and HBD activities in lactate dehydrogenase preparations and the differences in the interaction of these preparations with NAD analogues were examined. The results obtained were as follows. 1. The activity ratio between oxidation and reduction in LDH reaction is shown to be similar in both H4 and M4 preparations, whereas for HBD activity, the ratio seems to be lower in the M4 preparation than in H4(H4/M = 1/2). 2. NAD and its analogues (NXD, TNAD, and TNXD) are shown to be useful coenzymes for the LDH reaction, while 3-acetyl derivatives appear to be unsuitable for this purpose because of their lower activity. HBD activity with 3-acetyl NXD is shown to be higher than with TNAD or TNXD. among these NAD analogues, 3-acetyl NXD gives the highest HBD activity, especially in the M4 preparation. 3. The LDH activity of H4 relative to M4 preparations has been shown to be maximal when 450 mM lactic acid with NAD or 15 mM lactic acid with TNXD are used. Under these conditions, the contents of LDH subunits can be estimated with considerable reliability. As to HBD activity, the content of LDH subunit having HBD activity has been estimated by determing the enzyme activity under conditions in which either 300 mM 2-hydroxybutyrate with 3-acetyl NXD or 15 mM 2-hydroxybutyrate with NAD are employed.