Dissociation constants of glucan phosphorylases of rabbit tissues studied by polyacrylamide gel disc electrophoresis

The family of glycogen phosphorylases: structure and function

Glycogen phosphorylase plays a central role in the mobilization of carbohydrate reserves in a wide variety of organisms and tissues. While rabbit muscle phosphorylase remains the most studied and best characterized of phosphorylases, recombinant DNA techniques have led to the recent appearance of primary sequence data for a wide variety of phosphorylase enzymes. The functional properties of rabbit muscle phosphorylases are reviewed and then compared to properties of phosphorylases from other tissues and organisms. Tissue expression patterns and the chromosomal localization of mammalian phosphorylases are described. Differences in functional properties among phosphorylases are related to new structural information. Evolutionary relationships among phosphorylases as afforded by comparative analysis of proteins and gene sequences are discussed.

Electrophoretic analysis of liver glycogen phosphorylase activation in the freeze-tolerant wood frog

As an adaptation for overwinter survival, the wood frog, Rana sylvatica is able to tolerate the freezing of extracellular body fluids. Tolerance is made possible by the production of very high amounts of glucose in liver which is then sent to other organs where it acts as a cryoprotectant. Cryoprotectant synthesis is under the control of glycogen phosphorylase which in turn is activated in response to ice formation. To determine the mechanism of phosphorylase activation, a quantitative analysis of phosphorylase protein concentration and enzymatic activity in liver was carried out following separation of the phosphorylated a and nonphosphorylated b forms of the enzyme on native polyacrylamide gels. The results suggest that in gels, the b form is completely inactive, even in the presence of AMP and sodium sulfate, whereas the a form is active and stimulated 3-fold by these substances. Further, phosphorylase activation appears to arise solely from conversion of the b to a form of the enzyme without an increase in phosphorylase concentration or activation of a second isozyme. The quantitative analysis presented here should prove generally useful as a simple and rapid method for examining the physiological and genetic regulation of phosphorylase in animal cells.

Affinophoresis in two-dimensional agarose gel electrophoresis: specific separation of biomolecules by a moving affinity ligand

Affinophoresis is an electrophoretic separation technique for biomolecules which uses an affinophore. An affinophore is a macromolecular polyelectrolyte bearing affinity ligands. It migrates rapidly in an electric field, and consequently the electrophoretic mobility of molecules having affinity for the ligand is specifically changed. This technique has now been incorporated in two-dimensional agarose gel electrophoresis in a procedure which utilizes normal electrophoresis in the first dimension and affinophoresis in the second dimension. Proteins which do not have affinity for the ligand migrate to locations along a diagonal line passing through the origin, whereas proteins which have affinity are carried away from the line by the affinophore. Accordingly, molecules having affinity for the ligand can be readily assigned. Trypsins contained in Pronase and pancreatin were separated by this procedure using an affinophore bearing a competitive inhibitor for trypsin, benzamidine, on a polyanionic molecule (a polyacrylic acid derivative).

Determination of lectin-sugar dissociation constants by agarose affinity electrophoresis

Agarose crossed affinity electrophoresis (aff-EP) was employed for the determination of lectin-sugar dissociation constants (Ki). In the first dimension of the aff-EP increasing amounts of sugar (alpha-methyl-D-mannoside) were added to a given concentration of lectin (concanavalin A). Then the electrophoresis was run with alpha 1-acid glycoprotein, alpha 1-antitrypsin and alpha-fetoprotein as markers of lectin-sugar interactions. Mathematical equations for determination of the mechanisms and constants of lectin-sugar-glycoprotein interactions were developed. The mean value of the concanavalin A-alpha-methyl-D-mannoside dissociation constant calculated according to the introduced equations was 0.28 mM. In this system it was also possible to determine lectin-glycoprotein dissociation constants (K). The observed influence of the sugar on lectin-glycoprotein binding might be due to hydrophobic interactions since the addition of nonionic detergent caused reversal of this phenomenon.

Crystallization of pig skeletal phosphorylase b. Purification, physical and catalytic characterization

A new method for purification and crystallization of pig skeletal muscle phosphorylase b is presented. The ease of crystallization in the presence of 1 mM AMP and 1 mM spermine has permitted the study of some physical, chemical and enzymatic properties of the enzyme. The crystalline pig phosphorylase b gave a single band on SDS polyacrylamide gels of the same mobility as rabbit muscle phosphorylase subunit. Ultracentrifugation experiments showed that pig phosphorylase b exists in a dimeric form (S20,w = 8.4 S). No association occurred at 20 degrees C under conditions where rabbit phosphorylase b can be tetramerized; pig phosphorylase b was only 30% associated from dimer to tetramer at 13 degrees C. Pig phosphorylase b is highly stable to freezing and its specific activity did not change appreciably upon prolonged storage in the cold. Pig and rabbit phosphorylases b have comparable Vmax and Km values towards the substrate and the activator. However, there is an essential difference between the two enzymes in that pig phosphorylase b is not significantly inhibited by glucose 6-phosphate, which is a powerful inhibitor of the rabbit enzyme. Two different crystal forms of pig phosphorylase b were obtained which are small for X-ray diffraction studies. Diffusion of spermine into tetragonal crystals of rabbit phosphorylase b resulted in a difference Fourier synthesis at 3 A resolution that showed no strong indication of specific binding.

Affinity electrophoresis for monitoring terminal phosphorylation and the presence of queuosine in RNA. Application of polyacrylamide containing a covalently bound boronic acid

An affinity electrophoretic method has been developed to study the state of terminal phosphorylation of RNAs and the presence of the hypermodified base Q in tRNA. It is based on the copolymerization of acryloylaminophenylboronic acid into standard polyacrylamide gels and the interaction of this derivative with free cis-diol groups present in the RNA. In the case of terminal phosphorylation, free ribose groups are present either as such, or may be introduced by enzymatic reactions specific for a particular phosphorylation pattern (e.g. using T4 RNA ligase or guanylyltransferase). Additionally, tRNA species containing the Q base may be resolved from Q-lacking tRNAs by boronate affinity electrophoresis. The introduction of a non-destructive, one-step electrophoretic procedure not only offers an alternative to classical analytical methods, but also provides a means of isolating such populations of RNAs for which other methods are unavailable or are less convenient.

Poly(L-proline)-binding proteins from chick embryos are a profilin and a profilactin

Two poly(L-proline)-binding proteins (PBP-1 and PBP-2) were purified from chick embryos by using a poly(L-proline)-agarose column. PBP-1 was composed of two different polypeptides (molecular masses of 42 kDa and 15 kDa). The molar ratio of the two proteins in the complex was 1:1. The other poly(L-proline)-binding protein, PBP-2, was the 15-kDa protein itself. The 42-kDa protein was confirmed to be an actin from the amino acid composition, by immunochemical evidence and by its ability to self-polymerize. In addition, the 42 + 15-kDa protein complex (PBP-1) inhibited DNase I, just as a monomeric actin did. The amino acid composition of the 15-kDa protein was similar to that of mammalian profilin and it inhibited the salt-induced polymerization of rabbit skeletal muscle actin. Therefore, we conclude that the two poly(L-proline)-binding proteins from the chick embryo are a profilactin and a profilin in chick embryo. The ability of profilactin to bind poly(L-proline) must be due to profilin itself, because the profilin has a greater affinity for poly(L-proline) than does profilactin. Additionally, both the monomeric and filamentous actin from rabbit skeletal muscle have no affinity for poly(L-proline).

[Affinity electrophoresis in polyacrylamide gel. Influence of the concentration in the gel on the apparent affinity of cholinesterase for an anionic ligand site]

Affinity electrophoresis of three purified molecular forms of human plasma cholinesterase (monomer C1, dimer C3, tetramer C4) was carried out in polyacrylamide gels at various total acrylamide concentrations ranging from 3.48 to 9% in a discontinuous buffer system. A water-soluble linear copolymer supporting procainamide, a ligand of the anionic site of cholinesterase, was physically entrapped at various concentrations within the gel network. The combined effects of gel concentration and ligand concentration on the affinity pattern of the three molecular forms were studied. It was found that gel concentration influences the apparent binding activity of their anionic site: The apparent strength of interaction varied with the gel concentration: the denser the gel was, the higher the apparent affinity. The ligand-induced isomerization process was also depending on the gel concentration: the ligand concentration from which each zone is splitting into two moving zones decreased as the total gel concentration increased. These results show that the electrophoretic matrix plays an important role in the affinity process in affinity electrophoresis presumably by controlling kinetic effects: kinetics of protein-ligand complex formation and dissociation reactions, and mass transfer kinetics.

[Electrophoretic study of aged butyrylcholinesterase after inhibition by soman]

The following states of purified tetrameric form (C4) of human plasma butyrylcholinesterase were studied by electrophoretic techniques: native, inhibited by soman and by methane sulfonyl fluoride and soman-aged. In order to detect a significant conformational change of the aged cholinesterase as compared to the non-inhibited (native) species, enzymes were treated with a set of bifunctional reagents (diimidates) of different chain lengths. After denaturation, the cross-link products were subjected to sodium dodecyl-sulfate polyacrylamide gel electrophoresis. The peak areas of the cross-linked species and the parameters of cross-linkability were calculated from densitometric data, versus the maximal effective reagent length. The effect of occupancy of the esteratic site by substituted phosphonyl group and by methyl-sulfonyl residue on the binding activity of the anionic site was studied by affinity electrophoresis at varying temperatures with immobilized-procaïnamide as ligand. Apparent dissociation-constants of the enzyme-ligand complexes were estimated from measurement of mobilities versus ligand concentration. Corresponding thermodynamic quantities were calculated from Van't Hoff plots and basic thermodynamic equations. The reactivity of aged-cholinesterase with diimidates was similar to that of the native enzyme. Affinity for immobilized-procaïnamide was slightly lowered in aged and inhibited enzymes as compared to the native and sulfonylated enzymes. As for the ligand-induced isomerization of anionic site (A----B), revealed by affinity electrophoresis, the ligand concentration at the midpoint of transition (A = 0,5) was slightly greater for the aged enzyme than for the native one. From these results, the following conclusions can be drawn: the dealkylation of soman-cholinesterase conjugate (aging) does not seem to induce structural changes detectable in the cross-linkability of lysyle residues at the subunit interfaces and on the surface of the tetrameric enzyme. On the other hand, the affinity of the anionic site and ligand-induced isomerization process are altered in soman-inhibited and aged enzymes. These data suggest the occurrence of a weak conformational change of the active center and/or the formation of non-covalent bonds between the methylphosphonyl residue and side chain groups as a result of the dealkylation reaction.

[Multiple molecular forms of human plasma butyrylcholinesterase. II.-Study of the C1, C3 and C4 components by means of affinity electrophoresis (author's transl)]

Affinity electrophoresis has been applied to the analysis of the multiple molecular forms of human plasma cholinesterase allozyme U. A water-soluble p-amino-substituted-phenyltrimethylammonium polyacrylamide was synthetized by copolymerization of an unsaturated derivative of the ligand with acrylamide, and entrapped at various concentrations within the matrix of separating gels. Electrophoresis was carried out in these gels, and the relative mobility of the molecular forms of the enzyme was decreased. From the variation of mobility (Rm) as a function of immobilized ligand concentrations, the apparent dissociation constants of monomer (C1), dimer (C3) and tetramer (C4) of phenotype U were calculated. The decrease in mobility was reversed by addition of non-immobilized competitive ligands (N-methylpyridinium and N-methylacridinium). The appearance of the slopes of Rmi-1 vs. concentration does not give sufficient information for determination of the number of anionic binding sites of C4, but the slight curvature of the plots suggests that bivalent or higher interactions occur when the concentration is sufficiently high. For all three size isomers from a critical ligand concentration, a second zone, named B, appears and intensifies rapidly at the expense of the first zone (A) as the immobilized ligand concentration increases. Among several possible explanations of this phenomenon, it is proposed that the ligand induces a conformational isomerization of the enzymes with a change in affinity (KD,B less than KD,A) and that the interconversion process between the two states B in equilibrium A is slow compared with the ligand-association equilibrium dissociation steps.

Association constants of hybridoma antibodies specific for alpha (1 leads to 6) linked dextran determined by affinity electrophoresis

Binding constants of monomers of seven BALB/c IgM, four BALB/c IgA, and one C57BL/6 IgA anti-alpha (1 leads to 6) dextran hybridoma antibodies with dextran B512 and with isomaltoheptaose were determined by affinity electrophoresis. Bindings constants to dextran range from 1.52 X 10(5) to 4.43 X 10(5) ml/g for the five IgA monomers and from 1.70 X 10(3) to 6.10 X 10(4) ml/g for the seven IgM monomers. Antibody monomers containing both specific and nonspecific (derived from the myeloma cell that was used to generate the hybridomas) light chains are shown to have association constants with dextran 6 to 30-fold lower than monomers containing only specific light chain, suggesting that the association of specific heavy chain with nonspecific light chain does not result in an anti-dextran combining site. Binding constants with isomaltoheptaose range from 1.45 X 10(4) to 7.01 X 10(4)/M for the IgA proteins and from 6.46 X 10(3) to 7.70 X 10(4)/M for the IgM proteins. The binding constants with dextran and with isomaltoheptaose, and the electrophoretic, immunochemical and idiotypic characteristics of the hybridoma proteins are discussed.

Potato and rabbit muscle phosphorylases: comparative studies on the structure, function and regulation of regulatory and nonregulatory enzymes

Phosphorylases (EC 2.4.1.1) from potato and rabbit muscle are similar in many of their structural and kinetic properties, despite differences in regulation of their enzyme activity. Rabbit muscle phosphorylase is subject to both allosteric and covalent controls, while potato phosphorylase is an active species without any regulatory mechanism. Both phosphorylases are composed of subunits of approximately 100 000 molecular weight, and contain a firmly bound pyridoxal 5'-phosphate. Their actions follow a rapid equilibrium random Bi Bi mechanism. From the sequence comparison between the two phosphorylases, high homologies of widely distributed regions have been found, suggesting that they may have evolved from the same ancestral protein. By contrast, the sequences of the N-terminal region are remarkably different from each other. Since this region of the muscle enzyme forms the phosphorylatable and AMP-binding sites as well as the subunit-subunit contact region, these results provide the structural basis for the difference in the regulatory properties between potato and rabbit muscle phosphorylases. Judged from CD spectra, the surface structures of the potato enzyme might be significantly different from that of the muscle enzyme. Indeed, the subunit-subunit interaction in the potato enzyme is tighter than that in the muscle enzyme, and the susceptibility of the two enzymes toward modification reagents and proteolytic enzymes are different. Despite these differences, the structural and functional features of the cofactor, pyridoxal phosphate, site are surprisingly well conserved in these phosphorylases. X-ray crystallographic studies on rabbit muscle phosphorylase have shown that glucose-1-phosphate and orthophosphate bind to a common region close to the 5'-phosphate of the cofactor. The muscle enzyme has a glycogen storage site for binding of the enzyme to saccharide substrate, which is located away from the cofactor site. We have obtained, in our reconstitution studies, evidence for binding of saccharide directly to the cofactor site of potato phosphorylase. This difference in the topography of the functional sites explains the previously known different specificities for saccharide substrates in the two phosphorylases. Based on a combination of these and other studies, it is now clear that the 5'-phosphate group of pyridoxal phosphate plays a direct role in the catalysis of this enzyme. Information now available on the reaction mechanism of phosphorylase is briefly described.

Affinity diffusion II. Comparison between thermodynamic data obtained by affinity diffusion and precipitation in tubes

Association constants (Ka) of the precipitating system bovine serum albumin (BSA) goat anti-BSA were obtained at different temperatures via affinity diffusion (taking l/Kd - Ka) as well as via precipitation in tubes at optimal ratios. With affinity diffusion values of Ka of 0.6 to 1.1 x 10(5) l/M were found, whilst with precipitation in tubes Ka was from 3.3 to 11.2 X 10(7) l/M, using the same BSA and anti-BSA preparations. Via affinity diffusion binding energies delta F of approximately -6 to -7 kcal/M were found, with values of delta H close to zero, and a delta S of +23 entropy units. With precipitation in tubes these values were delta F -10.2 to -10.7 kcal/M, delta H -4.6 to -7.6 kcal/M and delta S +10 to +20 entropy units. The differences found with the two different methods must be ascribed to the fact that with affinity diffusion of precipitating antigen-antibody systems one just measures the interaction between the precipitating components with the highest dissociation constants, whilst with precipitation in tubes one measures the total energy of association of the system. With affinity diffusion and with precipitation in tubes, the same degree of positive entropy is observed. The system measured with affinity diffusion is approximately isothermic, whilst the total system, measured by precipitation in tubes, is strongly exothermic. Affinity diffusion still takes place at pH 9.5, at which pH no precipitation in the liquid phase takes place at optimal ratio; one may conclude from this that affinity diffusion mainly involves van der Waals interactions, as electrostatic bonding between BSA and anti-BSA is virtually abolished at that pH. This agrees well with the observation that the affinity diffusion reaction is isothermic.

Affinity electrophoresis of glycoproteins

Affinity electrophoresis is based on the reaction between interacting components during electro phoresis. In this review is given the general analytical technology. The main advantages of the analytical electrophoresis approach appear to be: 1. It can separate macromolecules that interact with a specific ligand from those that do not. 2. It can be used for studies of interacting macromolecules. 3. It is not necessary to purify interacting components. 4. A multitude of proteins reacting with the same ligand may be studied simultaneously. 5. It can be generalized to interactions other than those between lectins and glycoproteins.

Affinity diffusion. I. Method for measuring dissociation constants of precipitating antibodies

Dissociation constant (Kd) of antigen-antibody reactions can be obtained from the rates (measured by the progression of the precipitate vs. time) with which antigens diffuse into antibody-containing gels, as a function of antibody-concentration. A bovine serum albumin vs. rabbit anti-bovine serum albumin system was studied with whole antiserum and with its purified IgG fraction. A value was found for Kd of approximately 1.0 x 10-5 moles per liter. It is note- worthy that in monodimensional single diffusion gel precipitation systems of this type, the rate of progression of the precipitate front is significantly faster than the molecular diffusion coefficient of the antigen.

The effect of ligand presaturation on the interaction of serum albumins with an immobilized Cibacron Blue 3G-A studied by affinity gel electrophoresis

The interaction of the immobilized triazine dye Cibacron Blue 3G-A with rat, rabbit, sheep, goat, bovine and human serum albumins was studied by affinity gel electrophoresis. Dissociation constants were estimated in each instance and showed human serum albumin to have a significantly higher affinity for the dye than did albumin from any other species. Pretreatment of the defatted proteins with bilirubin (3 mol of bilirubin/mol of protein) did not increase the dissociation constants of the serum albumins, whereas pretreatment with palmitate (7 mol of palmitate/mol of protein) increased the dissociation constant in all cases: 3-fold for human serum albumin, 15-fold for other serum albumins. Increasing the bilirubin/albumin ratio (to 7:1) did not affect the dissociation constant of the albumins studied. Decreasing the palmitate/albumin ratio decreased the dissociation constant for human serum albumin, but did not affect those of bovine and rat albumins. Altering the chain length of the presaturating fatty acid dramatically changed the dissociation constant of both human and bovine serum albumins. Butyrate, hexanoate, octanoate and decanoate did not significantly influence the dissociation constants of bovine and human serum albumins for Cibacron Blue, whereas laurate, myristate and palmitate greatly increased the dissociation constant. These data are discussed in relationship to the behaviour of albumins during dye--agarose column chromatography. In Addendum the effect of nucleotide presaturation on the interaction between Bacillus stearothermophilus 6-phosphogluconate dehydrogenase and the immobilized triazine dyes Cibacron Blue 3G-A and Procion Red HE-3B was examined, and the implications for dye--ligand chromatography are discussed.

Phosphorylation of McArdle phosphorylase induces activity

In McArdle disease, myophosphorylase deficiency, enzyme activity is absent but the presence of an altered enzyme protein can frequently be demonstrated. We have found that phosphorylation of this protein in vitro can result in catalytic activity. We studied muscle of four patients; all lacked myophosphorylase activity, but myophosphorylase protein was demonstrated by immunodiffusion or gel electrophoresis. Incubation of muscle homogenate supernatants with cyclic AMP-dependent protein kinase and ATP resulted in phosphorylase activity. The activated enzyme comigrated with normal human myophosphorylase in gel electrophoresis. Incubation with [gamma-32P]ATP resulted in incorporatin of 32P into the band possessing phosphorylase activity. Activation of phosphorylase by cyclic AMP-dependent protein kinase was inhibited by antibodies to normal human myophosphorylase or by inhibitory protein to cyclic AMP-dependent protein kinase. Incubation of muscle homogenates with phosphorylase b kinase and ATP also resulted in phosphorylase activity. After the action of cyclic AMP-dependent protein kinase, the resulting activity was similar to that of phosphorylase b. However, incubation with phosphorylase kinase resulted in activity similar to that of phosphorylase a. For several reasons, it is not likely that McArdle disease is due to lack of normal phosphorylation, but restoration of activity to the mutant protein by phosphorylation may provide a clue to understanding the mechanism of this genetic defect.

Affinity titration curves: determination of dissociation constants of lectin-sugar complexes and of their pH-dependence by isoelectric focusing electrophoresis

By performing electrophoresis perpendicular to a stationary pH gradient (pH-mobility curves) in polyacrylamide gels containing a specific ligand either covalently fixed or entrapped in the gel matrix, it is possible to measure dissociation constants (Kd) and their pH-dependence in the pH range 3.5-10. The present technique, called 'affinity titration curves', is an extension of 'affinity electrophoresis'. This system has been applied to the study of the interaction between lectins and sugars: lectin from Ricinus communis seeds and alpha-D-galactose, and lectin from Lens culinaris seeds and alpha-D-mannose. The pH-dependence of Kd values indicated a more rapid decrement of affinity of both lectins for their ligands at acidic pH as compared to alkaline pH. For both lectins, maximum affinity was found in the pH range 7-8. Since the ionic strength of focused carrier ampholytes is 100-200-times lower than in conventional electrophoresis, the Kd values found by the present method are generally lower than the same values obtained by affinity electrophoresis.

Studies on lectins. XLIX. The use of glycosyl derivatives of Dextran T-500 for affinity electrophoresis of lectins

p-Aminophenyl glycosides and glycosylamines were coupled to periodate oxidized Dextran T-500 either directly or through an epsilon-aminocaproic acid spacer. The new glycosylated derivatives of dextran specifically precipitate lectins having the appropriate carbohydrate specificity, and thus were used in the preparation of affinity gels for affinity electrophoresis of lectins. The apparent strength of interaction of several lectins with carbohydrate residues immobilized in this way was less than with carbohydrates immobilized in O-glycosyl polyacrylamide copolymers. The presence of epsilon-aminocaproic spacer had no effect on the strength of interaction. The advantages of this type of macromolecular derivative of the ligand for affinity electrophoresis and some differences between the glycosylated dextrans and O-glycosyl polyacrylamide copolymers are discussed. Dextrans containing bound p-aminophenyl alpha-D-mannopyranoside and p-aminophenyl alpha-D-glucopyranoside were used to study the binding properties of concanavalin A and the lectin from Lathyrus sativus seeds. For the investigation of interaction of lectins from Ricinus communis and Glycine soja seeds, dextran derivatives containing bound p-aminophenyl alpha- and beta-D-galactopyranosides and alpha- and beta-D-galactopyranosylamines were used.

Study of the interaction between NADP-dependent dehydrogenase and immobilized adenosine 2'-monophosphate by means of affinity electrophoresis

A water-soluble 8-substituted adenosine 2'-monophosphate-polyacrylamide (8-sub-2'-AMP-PA) was prepared as a new affinity ligand for the determination of the dissociation constants of the interactions between immobilized 8-sub-2'-AMP and NADP-dependent dehydrogenases (NADP-dependent DH), NAD-dependent dehydrogenases (NAD-dependent DH) and phosphorylase by means of affinity electrophoresis. From the dissociation constants, it was found that NADP-dependent DH had a much stronger affinity to immobilized 8-sub-2'-AMP than did NAD-dependent DH and phosphorylase. On the other hand, NADP-dependent DH had a much weaker affinity to immobilized 8-sub-5'-AMP than did NAD-dependent DH. The effects of NADP+ and NAD+ on the interaction between immobilized 8-sub-2'-AMP and NADP-dependent DH were also investigated by means of affinity electrophoresis. NADP+ inhibited the interaction specifically, but NAD+ did not inhibit the interaction. These results indicate that 8-sub-2'-AMP binds to the coenzyme binding site of NADP-dependent DH, while other compounds, such as 8-sub-5'-AMP and NAD+, do not bind to NADP-depenndent DH. Such a difference suggests that the phosphate group at position 2' in 2'-AMP and NADP+ is important for the binding at the coenzyme binding site of NADP-dependent DH.

Histochemical observations of polyglucose synthesized by enzyme activities in human gastric carcinoma

Polyglucose particles histochemically synthesized from glucose 1-phosphate by phosphorylase and branching glycosyltransferase were observed in the gastric carcinoma cells, in intestinal metaplastic epithelium of the gastric mucosa and in fetal epithelium of the fetal gastric mucosa by light and electron microscopical studies. Light microscopical observations resembled those in previous reports. As for the electron microscopical observations, in gastric carcinoma cells, the polyglucaose synthesizing area were expansively widened by a deposition of synthesized polyglucose particles. Three patterns of their intracellular distribution, (Focal type, scattered type and singly deposited type) were observed. Besides, two types of polyglucose particle were synthesized. One type appeared as monoparticles which were relatively similar in size and the other type appeared as rosette-like structures which varied in size. Larger polyglucose particles which resembled the polyglucose particle synthesized in the fetal epithelium were observed among them. In the intestinal metaplastic epithelium, polyglucose particles which were similar in size were synthesized in narrow focal areas of the cytoplasmic matrix. The distribution, shape and size of polyglucose particles synthesized in the carcinoma cells were irregular as compared with those in the intestinal metaplastic elpithelium. It seems that these irregularities were due to the influence of enzymne deviation caused by carcinoma.

Determination of the interaction of lactate dehydrogenase with high-molecular-weight derivatives of AMP by affinity electrophoresis

The interaction of lactate dehydrogenase with high-molecular-weight derivatives of AMP was studied by affinity electrophoresis in an alkaline buffer system and by means of kinetic measurements. AMP was coupled to synthetic hydroxypropylmethacrylamide copolymers through glycine, 6-aminohexanoic and 12-aminododecanoic spacer arms. The values of the dissociation constants (K) of the lactate dehydrogenase isoenzymes--immobilized AMP complexes determined by affinity electrophoresis decreased with increasing length of the spacer arm. Lactate dehydrogenase was competitively inhibited by high-molecular-weight derivatives of AMP; values of the inhibition constants (Ki) also depended on the spacer arm: the longer the spacer arm the stronger was the interaction between the enzyme and the inhibitor. Ki values for high-molecular weight derivatives of AMP were lower than those obtained for free AMP.

binding constants of levans and D-fructo-oligosaccharides to BALB/c and NZB D-fructan-specific, myeloma proteins, determined by affinity electrophoresis

The association constants for the interaction of BALB/c (UPC 10, Y5476, W3082, and UPC 61) and NZB (PC 3660) myeloma anti-D-fructans in pure form, or in ascitic fluids, with high-molecular-weight levans (Ka) and with such low-molecular-weight compounds as rye-grass levan, inulin, sucrose, and D-fructo-oligosaccharides (Kia) were determined by affinity electrophoresis, measuring the extent of retardation of the D-fructan-specific band by levan and its restoration by the low-molecular-weight compounds and oligosaccharide haptens. With different levans,Ka values ranged from 1.14 X 10(5) TO 1.52 X 10(6) ML/g for PC 3660, 1.35 X 10(5) TO 6.45 X 10(5) mL/g for UPC 10, 1.0 X 10(4) to 7.9 X 10(4) mL/g for Y5476, 7.63 X 10(3) to 6.38 X 10(4) mL/g for W 3082, and 3.35 X 10(3) to 1.54 X 10(4) mL/g for UPC 61. The retarded, D-fructan-specific bands of W3082 and UPC 61 were restored by inulin, having beta-D-(2 leads to)-linkages, and rye-grass levan, having beta-D-(2 leads to 6)-linkages, and those of PC 3660, UPC 10, and Y5476 by rye-grass levan. The Kia values of inulin with W3082 and UPC 61 were 10 times those of rye-grass levan. The Kia values of inulin (3.65 X 10(5) M-1 for W3082, and 4.44 X 10(5) M-1 for UPC 61) were very similar to those of [beta-D-Fruf-(2 leads to 1)]2-beta-D-Fruf-(2 leads to 6)-D-Glc (3) (3.95 X 10(5) M-1 for W3082, and 4.5 X 10(5) M-1 for UPC 61). With sucrose and the D-fructo-oligosaccharides, the order of Kia values of W3082 and UPC 61 was 3 greater than beta-D-Fruf-(2 leads to 1)-beta-D-Fruf-(2 leads to 6)-D-Glc greater than sucrose greater than beta-D-Fruf-(2 leads to 6)-D-Glc. With rye-grass levan, Kia values were 4.25 X 10(5) M-1 for PC 3660, 2.7 X 10(5) M-1 for UPC 10, and 8.77 X 10(4) M-1 for Y5476. These results confirm earlier findings that W3082 and UPC 61 have dual specificity for beta-(2 leads to 1) and beta-(2 leads to 6) D-fructofuranosyl linkages, that PC 3660, Y5476, and UPC 1U have specificity for beta-(2 leads to 6) D-fructofuranosyl linkages, and that the combining sites of W3082 and UPC 61 are most complementary to the tetrasaccharide 3. That W3082 and Y5476 share the same, cross-reacting idiotype, although their combining sites differ in specificity, provides further evidence that these two properties do not run parallel.

Study of the interaction between L-lactate dehydrogenase isoenzymes and immobilized 8-substituted adenosine 5'-monophosphate by means of affinity electrophoresis

A water-soluble 8-substituted adenosine 5'-monophosphate-polyacrylamide (8-sub-5'-AMP-PA) was prepared as an affinity ligand for the affinity electrophoresis of L-lactate dehydrogenase (LDH). According to the principles of affinity electrophoresis, the dissociation constants of the interaction between immobilized 8-sub-5'-AMP and rabbit LDH isoenzymes [LDH-1(H4), LDH-2(H3M), LDH-3(H2M2), LDH-4(HM3) and LDH-5(M4)], beef LDH-1(H4) and LDH-5(M4) and pig LDH-1(H4) were calculated. Both rabbit and beef LDH-5 (muscle-type isoenzymes) had approximately a 35-fold stronger affinity to immobilized 8-sub-5'-AMP than has their LDH-1 (heart-type isoenzymes). The effects of free nucleotides on the interaction between immobilized 8-sub-5'-AMP and LDH isoenzymes were also investigated by affinity electrophoresis. NAD+ has a stronger affinity to LDH-5(M4) than had 5'-AMP and 5'-IMP, while NMN, adenosine and fructose 6-phosphate had no affinity.

Microheterogeneity of rat glycogen phosphorylase liver-type isozyme

We devised a method of polyacrylamide gel electrophoresis at pH 7.3, modified by omitting base catalyst, N,N,N',N'-tetramethylethylenediamine, in the preparation of separating gels. Using this method, both liver and liver-like types of rat glycogen phosphorylase (1,4-alpha-D-glucan:orthophosphate alpha-glucosyl-transferase, EC 2.4.1.1) were resolved into multiple forms, about 6-10, although either of them was purified to a single protein with the same molecular size on sodium dodecyl sulfate gel electrophoresis. The microheterogeneity of these two types was also confirmed by isoelectric focusing in polyacrylamide gels (pH 5-8). The major isoelectric points of the liver type phosphorylase were between 5.72 and 5.86, but those of the liver-like type were between 5.86 and 5.92, and so the former had slightly but significantly lower isoelectric points than the latter. However, the both types were not distinguished immunologically. The brain and muscle types of rat phosphorylase did not show such a distinct heterogeneity by the same electrophoresis methods.