Neutral arylamidase in urine of healthy and nephrotic children

Influence of the insecticides acetamiprid and carbofuran on arylamidase and myrosinase activities in the tropical black and red clay soils

The objective of this study was to determine the effects of two insecticides, namely, acetamiprid and carbofuran on the enzymatic activities of arylamidase (as glucose formed from sinigrin) and myrosinase (as β-naphthylamine formed from L-leucine β-naphthylamide) in the black and red clay soils collected from a fallow groundnut (Arachis hypogaea L.) fields in the Anantapur District, Andhra Pradesh, India. The study was realized within the framework of the laboratory experiments in which the acetamiprid and carbofuran were applied to the soils at different doses (1.0, 2.5, 5.0, 7.5, 10.0 kg ha(-1)). Initially, the physicochechemical properties of the soil samples were analyzed. After 10 days of pesticide application, the soil samples were analyzed for the enzyme activities. Acetamiprid and carbofuran stimulated the arylamidase and myrosinase activities at lower concentrations after 10 days incubation. Striking stimulation in soil enzyme activities was noticed at 2.5 kg ha(-1), persists for 20 days in both the soils. Overall, higher concentrations (5.0-10.0 kg ha(-1)) of acetamiprid and carbofuran were toxic or innocuous to the arylamidase and myrosinase activities. Nevertheless, the outcomes of the present study clearly indicate that the use of these insecticides (at field application rates) in the groundnut fields (black and red clay soils) stimulated the enzyme (arylamidase and myrosinase) activities.

[Urinary elimination of multiple forms of gamma-glutamyltranspeptidase and aminopeptidase (author's transl)]

Concentrated and dialyzed 24-h urines of healthy persons were separated by 105000 X g ultracentrifugation into a pellet (P105) and a supernatant (S105) fraction. Chromatography of the P105 fraction on Sepharose 4B and 2B revealed that gamma-glutamyltranspeptidase and aminopeptidase activities had a molecular mass of 20 X 10(5) to 40 X 10(6), whereas in the S105 fraction soluble gamma-glutamyltranspeptidase and aminopeptidase had 86000 and 160000, respectively. Triton X-100 solubilization was performed on the P105 fraction and on a human renal cortex 40000 X g pellet, used as a reference. All the activity was recovered in both cases in a single peak of detergent gamma-glutamyltranspeptidase and detergent aminopeptidase eluted by filtration on Ultrogel Ac A22. Apparent molecular mass of Triton X-100 solubilized urinary and renal enzymes were 250000 and 243000 for gamma-glutamyltranspeptidase, and 298000 for both aminopeptidases. Protease solubilized forms were obtained by trypsic digestion of detergent urinary and renal forms. Both gamma-glutamyltranspeptidases were found to have an apparent molecular mass of 86000 on Sephadex G 150, which is identical to the value found for the S105 urinary gamma-glutamyltranspeptidase. The aminopeptidases had 238000 and 232000, which is a higher value than the molecular mass of the S105 urinary aminopeptidase. This letter could be a degraded form of the renal aminopeptidase. These findings suggest that gamma-glutamyltranspeptidase and aminopeptidase in the P105 fraction are similar to native renal enzymes. Evaluation of the P105 fraction enzymatic activities may thus be useful in the diagnosis of tubular damage.

Angiotensin I-converting enzyme in human urine

It was demonstrated that angiotensin I-converting enzyme was excreted in human urine. The mean activity of the enzyme in normal urine was found to be 0.38 +/- 0.04 (S.E.M.) units/day (n = 18) and the enzymic activity correlated well with the concentration of the excreted sodium (r = 0.76, p less than 0.005). Urinary angiotensin I-converting enzyme was partially purified. Three different molecular weights of enzyme (greater than 400 000, 290 000 and 140 000) were demonstrated by Sephadex G-200 gel filtration. The enzymic properties of these three enzymes were identical with those of angiotensin I-converting enzyme from human lung with regard to inhibitory effects (bradykinin potentiator c and Arg-Pro-Pro), Cl- dependency, pH optimum and KM value.

Comparison of soluble and membrane-bound neutral arylamidases from renal cell carcinoma

Soluble and membrane-bound neutral arylamidases from renal cell carcinoma were partially purified and their properties were compared. Soluble neutral arylamidase was a heat labile and SH-dependent metalloenzyme. Membrane-bound neutral arylamidase was a rather heat stable metalloenzyme and was activated by Co2+ with changing KM and VMAX. KM values for soluble and membrane-bound neutral arylamidases were different. L-Methionine (5mM) did not affect the enzymic activity of soluble neutral arylamidase, but inhibited 82 percent of the enzymic activity of membrane-bound neutral arylamidase. Molecular weights of soluble and membrane-bound neutral arylamidases by Sephadex G-200 gel filtration were 140000 and 240000, respectively. Soluble and membrane-bound neutral arylamidases from renal cell carcinoma appear to be distinct enzymes.

Comparison of human membrane-bound neutral arylamidases from small intestine, lung, kidney, liver and placenta

Human membrane-bound neutral arylamidases were solubilized from small intestinal mucosa, lung, kidney, liver and placenta with trypsin. These five membrane-bound neutral arylamidases were identified by polyacrylamide gel-disc electrophoresis. The heat sensitivity of each enzyme was in the order, liver and placenta greater than kidney greater than lung greater than small intestine. This order correlates with that of electrophoretic mobility, except for the placental membrane-bound neutral arylamidase. Five membrane-bound neutral arylamidases have the same molecular weight, 240 000, as estimated by Sephadex G-200 gel filtration. The five membrane-bound neutral arylamidase have very similar KM values (8.7 x 10(-5) M towards L-alanyl-beta-naphthylamide), optimal pH values, hydrolysis ratios towards L-alanyl-beta-naphthylamide and L-leucyl-beta-naphthylamide, and sensitivities of inhibition by chelators or amino acids. These results suggest that the multiple forms of membrane-bound neutral arylamidase found in five different human organs are organ-specific isoenzymes.