Comparative characteristics of acetylcholinesterase preparations from human erythrocytes with varying degrees of purity

Preparations of human erythrocyte acetyl cholinesterase (HEACE) that differed in their specific activities (0.7 to 4.1 U/mg) and the final purification method were examined for protein and isoenzymic spectrum (by polyacrylamide gel disc electrophoresis), catalytic properties in the reaction of acetytriocholine hydrolysis, sensitivity to the specific organophosphorus inhibitor Gd-42, concentrations of active centres of HEACE, and activity of one catalytic centre. The preparations showed a stable spectrum of 11-12 proteins: HEACE had molecular heterogeneity and was electrophoretically separated into 3 fractions that differed in their aggregation level. Preparations with varying specific activity contained different HEACE quantities. Regardless of the purification degree, HEACE displayed similar activity of the catalytic centre and enzymic properties in reactions with the substrate and inhibitor.     

Adenosine deaminase activity in hepatomas of varying degrees of malignancy]

In highly malignant Gelshtein 22A hepatcma and ascites Ehrlich carcinoma adenosine deaminase activity was found to be reduced 3-fold as compared with that of the normal mouse liver. In less malignant hepatomas adenosine deaminase activity drops only by 20%. A certain reduction of adenosine deaminase activity was also noted in the liver to tumour-bearing mice.     

Extraction of rifamycin B from native and aqueous solutions]

Optimal conditions for extraction of rifamycin B from aqueous solutions and fermentation broth filtrates at pH values within 2.0-7.0 were determined. When the antibiotic was extracted from the aqueous solutions, the highest yield was obtained at pH 2.0. When the antibiotic was extracted from the fermentation broth filtrates, it was found that chloroform was the most selective solvent with respect to rifamycin B, the chloroform selectivity being increased at pH 3.5-4.0. It was shown that rifamicin B passed from the buffer solutions with a concentration of 3-20 mg/ml to chloroform in amounts of 6-7 mg/ml and to ethylacetate and butanol in amounts of 20 mg/ml. Such conditions of chloroform and butanol (9 : 1) increased the rifamycin B contents in the extract up to 40 mg/ml.     

Transformation of rifamycin B with immobilized rifamycin oxidase of Curvularia lunata

Rifamycin oxidase of Curvularia lunata was immobilized on polyacrylamide gel. The optimum pH and temperature for immobilized enzyme reaction were 6.5 and 50 °C, respectively. Enzyme stability increased on immobilization and the half lives of immobilized enzyme preparations at 30 and 40 °C were 30 and 11.5 d, respectively. With 2.5 mm beads diffusional resistances were observed. Reusability studies showed that 1 mm size beads gave a higher rate of transformation in comparison with 2 or 2.5 mm beads.     

Determination of biological activity of hydrogel preparations based on ketoconazole and clotrimazole]

Biological activity of original hydrogel preparations based on ketoconazole and clotrimazole was estimated biologically with the 3-dose variant of the agar-diffusion method. The optimal concentrations of the active substances in the hydrogels were the following: 2% of ketoconazole and 1% for clotrimazole.     

The relationship of purity to photosynthetic activity in preparations ofCodium fragile chloroplasts

Summary The purity of the chloroplasts isolated from the algaCodium fragile by 1. a conventional centrifugation method, and 2. a method involving a gel filtration stage through Sephadex G 50 coarse, was compared using enzymatic analysis in conjunction with electron microscopy. The findings show that the purer chloroplasts, obtained by gel filtration, could carboxylate more¹⁴CO₂ and evolve more O₂ than the crude preparation from which they originated.     

Chromatographic control of the process of rifamycin B isolation and purification]

A method of chromatography in a thin layer of Silica Cel No. 2 was developed for rifamicin B, rifamicin complex and some admixtures. Extracts of rifamicin B in an organic solvent, aqueous buffer reextracts and dry preparations of rifamicin B were analyzed with the above method. A half-quantitative chromatographic procedure for estimation of the main admixture in dry preparations was proposed.     

Stability of rifamycin B in aqueous solutions

Stability of rifamycin B in aqueous solutions at various values of pH and temperature was studied. It was shown that inactivation of the antibiotic in neutral and alkaline solutions proceeded according to the first order equation. In acid solutions rifamycin B was oxidized with air oxygen to form rifamycin O.     

Comparative determination of lipase activity in pharmaceutical preparations]

Lipase activity in various pharmaceuticals has been assayed with different methods expressing the results in different units. Conversion factors enabling comparison of the international and Wallersteins units in FIP units which is current way of pancreatin enzyme activity expression have been calculated. Lipase activity conversion factors are diversified and depend on the type of pharmaceutical preparation containing pancreatic extract. Conversion factors facilitate comparison of lipase activity in different Polish and foreign-made pharmaceutical preparations and proper dosage.     

Ribonuclease activity in preparations of human leukocyte interferon]

Preparations of human leukocyte interferon obtained by multi-stage purification procedure exhibited ribonuclease activity with the optimum at pH 7.0--7.5. The enzyme possessed the endonuclease action mechanism. Most substances studied for their effect on the RNA-ase activity in human interferon preparations showed many of them to act on the enzyme in the same way as on other ribonucleases. However, dithioerythritie, a reducing agent for disulfide bounds, activated the ribonuclease in the interferon preparation, as distinct from the pancreatic ribonuclease, which was inhibited by this preparation. Patterns of protein and RNA-ase distribution were obtained by electrophoresis in polyacrylamide gel.     

Protein functional groups of the ova in the roach and carp-bream of varying degrees of maturity]

The Black Sea roach and carp-bream eggs of different degree of maturity differ from each other by the content of SH-, S--S-groups of proteins and non-protein low molecular weight thiol compounds. Definite differences were found in the optical density of soluble proteins and degree of ionization of their side groups.     

Contraceptive activity of combinations of steroids and antiadrenergic preparations]

Experiments were conducted on mature female rats. Simultaneous administration through a tube for 14 days, daily, of mestranol (0.04 mg/kg) and megestrol acetate (0.8 mg/kg) gave no significant contraceptive effect, whereas the use of steroid preparations in the same doses in combination with antiadrenergic substances--dopegit (100 mg/kg) or pyrroxan (10 mg/kg) prevented pregnancy effectively.     

Activity, isoenzymes and purity of mushroom tyrosinase in commercial preparations

Several lots of commercial tyrosinase preparations were examined with regard to their enzyme activity, isoenzyme composition and purity. Enzyme activity toward catechol, -dopa and tyrosine showed significant variations from lot to lot and activation by SDS. Distribution of isoenzyme forms also varied from lot to lot. Comparisons of electrophoretic and isoelectric focusing protein profiles showed considerable differences and distributions of the proteins in each sample. Tyrosinase appeared to be a minor component in each preparation when compared to a partially purified enzyme. Investigators using commercial tyrosinase should exercise caution in interpreting data due to the presence of different isoenzyme forms, their distribution in various lots, and the presence of numerous other proteins.