Studies on kinetic parameters and stability of aminoacylase in non-conventional media.

Catalytic properties and conformational stability of aminoacylase (N-acylamino acid amidohydrolase, EC 3.5.1.

The effect of environmental pollution on the function of enzymes of active skeleton muscle. Part 1: An adequate method to study the effect of metal ions on the activity of phosphofructokinase.

The possibilities of exact measuring the effect of metal ions on the activity of phosphofructokinase (PFK) by means of both a heat inactivation and an auxiliary enzyme system were studied. It was found that both methods are suitable for measuring the inhibition of phosphofructokinase by metal ions. It was further found that metal ion concentrations causing 50% deactivation of PFK could not considerably influence the measuring capacity of the auxiliary enzyme system.

Effects of paraquat treatment on fish transaminase molecular subforms.

The effects of paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridylium dichloride) treatment were investigated in carp, silver carp and wels. The serum glutamic-oxalacetic transaminase (GOT; L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.

Factors influencing the operation of a vertical bioreactor segmented with perforated plates.

Factors influencing the operation of a vertical bioreactor segmented with perforated plates supporting immobilized yeast cells were studied. It was found that the most important factors are the length-diameter (L/D) ratio of the reactor and the dilution rate. It was supposed that the optimal L/D ratio is about 1.

Immobilization of pig muscle aldolase on a silica-based support.

Pig muscle aldolase was covalently attached to a silica-based support possessing aldehyde functional groups. The activity of the immobilized enzyme was 37 U/g solid, and the specific activity calculated on a bound protein basis was 1.9 U/mg protein.

[Immobilization of glucose oxidase on silica-based supports].

Glucose oxidase (beta-D-glucose: oxygen 1-oxidoreductase, EC 1.1.3.

Determination of glycolytic intermediates in a flow injection system using immobilized enzymes.

Some glycolytic enzymes (lactate dehydrogenase, pyruvate kinase, enolase and phosphoglyceromutase) were immobilized on a polyacrylamide-type bead polymer containing carboxylic functional groups activated by water-soluble carbodiimide. The immobilized enzymes were used for the determination of pyruvic acid, phosphoenolpyruvic acid, 2-phosphoglyceric acid and 3-phosphoglyceric acid in a flow injection system. The immobilized lactate dehydrogenase column was repeatedly employed for the determination of pyruvic acid in clinical samples.

Immobilization of lactate dehydrogenase on polyacrylamide beads.

Pig muscle lactate dehydrogenase (L-lactate:NAD oxidoreductase, EC 1.1.1.

Enzymatic determination of isocitrate by amperometric monitoring of the rate of oxygen consumption.

A coupled enzymatic method elaborated for NAD+-dependent dehydrogenases has been adapted for NADP+-dependent isocitrate dehydrogenase, in combination with amperometric measurements. The isocitrate dehydrogenase activity dependent linearly on the isocitrate concentration in the range 0-2 X 10(-4) M. Application of this method affords a sensitive estimation of isocitrate even in turbid liquids such as fermentation broths.

Comparative studies on soluble and immobilized rabbit muscle pyruvate kinase.

Rabbit muscle pyruvate kinase was immobilized by covalent attachment to a polyacrylamide support (Akrilex C) containing carboxylic functional groups. As a result of immobilization, the pH optimum for catalytic activity shifted into a more alkaline direction. The apparent Km value with phosphoenolpyruvate increased, and that with ADP slightly decreased.

Characterization and comparison of soluble and immobilized pig muscle aldolases.

Pig muscle aldolase was insolubilized by covalent attachment to a polyacrylamide matrix containing carboxylic functional groups. The catalytic activity of the Akrilex C-aldolase was 2014 units/g solid, i.e.

Studies on the properties of glucose-6-phosphatase from carp liver microsomes (Cyprinus carpio L.).

The effects of temperature and pH on the phosphohydrolase activity of carp hepatic glucose-6-phosphatase (EC 3.1.3.

A novel polyacrylamide-type support prepared by p-benzoquinone activation.

A new and simple method for the activation of polyacrylamide gels using p-benzoquinone is described. The optimal conditions of activation have been elaborated. The activated support could be successfully applied to the immobilization of ligands having nucleophilic groups active over a broad pH range.

Morphological and biochemical studies on liver, kidney and gill of fishes affected by pesticides.

Effect of a herbicide, paraquat (1,1'-dimethyl-4,4'-bipyridilium-dichloride), the fungicide copper sulphate, and zinc chloride was studied on the histological structure of liver, kidney and gill of three fish species with different feeding habits, viz.: a herbivorous, silver carp (Hypophthalmichthys molitrix); an omnivorous, common carp (Cyprinus carpio L.) and a carnivorous, sheatfish (Silurus glanis L.

Studies on the effect of paraquat on glycogen mobilization in liver of common carp (Cyprinus carpio L.).

1. A herbicide, paraquat (1,1'dimethyl-4,4'-bipyridilium-dichloride) was administered to carp in 0.5-10.

Characterization of enzyme-enzyme interaction using an affinity batch system.

NAD-Sepharose 4B gel was used to study the complexation between glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating) EC 1.2.1.

Comparative studies on the sensitivity of different fish species to metal pollution.

The effects of 10 ppm CuSO4, ZnCl2 on the blood glucose level and serum LDH, GOT, GPT activities of three fish species (carp, silver carp, European wels) were measured. CuSO4 increased the blood glucose level, LDH, GOT and GPT activities in the three species in the following order: silver carp greater than carp greater than European wels. ZnCl2 did not alter the same levels.

Investigation of the active center and catalytic mechanism of porcine kidney aminoacylase: a model of the active center.

Procine kidney aminoacylase (E.C. 3.

Complex of D-glyceraldehyde-3-phosphate dehydrogenase with Cu2+ ion. I. The apoenzyme-Cu complex.

D-Glyceraldehyde-3-phosphate dehydrogenase binds one Cu2+ ion per subunit, which results in the formation of a specific metal-protein complex. This complex exhibits a sharp absorption band around 370 nm, and a broad, small absorption band in the 600-700 nm region. The shape of the absorption spectrum of Cu-GAPD complex in the visible range depends on the anionic composition of the solution.

Complex of D-glyceraldehyde-3-phosphate dehydrogenase with Cu2+ ion. The properties of ternary Cu-enzyme-coenzyme complex.

The formation of ternary Cu-enzyme-coenzyme complex from cupric ion and D-glyceraldehyde-3-phosphate dehydrogenase holoenzyme results in similar spectral changes as the formation of binary Cu-apoenzyme complex, which indicates that the complex bonds between cupric ion and the holoenzyme, and cupric ion and the apoenzyme are similar. Spectrophotometric titration, chemical modification experiments and inhibition studies with cupric ion gave evidence that cupric ion is selectively bound on Cys-149 residue also in the Cu-GAPD-NAD complex. The charge transfer interaction between the coenzyme and Cu-GAPD, i.