[Kinetics of thermoinactivation of intracellular cholesterol oxidase]. / Issledovanie kinetiki termoinaktivatsii vnutrikletochnoi kholesterinoksidazy.

It was shown that thermoinactivation of cholesterol oxidase in solution obeys the first order kinetics. The inactivation rate constants do not depend on concentrations of the enzyme, serum albumin and nonionic detergent Tween-80 and increase with a rise in ionic strength of the buffer solution and NaCl. Thermoinactivation is accompanied by a hypsochromic shift of the absorption maxima both in the short- and long-wave regions of the enzyme UV spectrum. It is assumed that the observed inactivation is due to conformational changes in the protein molecule which cause the loosening of its binding to the cofactor as well as the split-off of the latter. The value of activation energy for this process is 255 kJ/mol.

[Composition and properties of cholesterol oxidase from Actinomyces lavendulae]. / Issledovanie komponentnogo sostava i svoistv kholesterinoksidazy Actinomyces lavendulae.

The composition of cholesterol oxidase isolated by different methods from the Actinomyces lavendulae mycelium was studied by gel-chromatography. It was shown that depending on the isolation conditions the enzyme can be detected within the complexes with different molecular weights. The values of pH, pI and Km for the isolated components were determined. The thermal inactivation of the cholesterol oxidase components at different temperature intervals was investigated.

[Isolation and characterization of lipase from Geotrichum asteroides FKM F-144]. / Vydelenie i nekotorye svoistva lipazy Geotrichum asteroides VKM F-144.

By gel chromatography on Sephadex G-75 it has been demonstrated that the culture fluid of Geotrichum asteroides VKM F-144 contains two lipolytic components, one of which, lipase 1, eluates in the free volume of the column, whereas the second component, lipase 2, eluates in the volume close to that of the egg albumin yield. The paper describes a method for lipase 2 preparation consisting of precipitation of accompanying compounds at pH 4.2, depigmentation of the supernatant on the resin PAP in the Cl-form, selective sorption of lipase on the cation exchange resin CMC and further purification of the eluate gel chromatography and Sephadex G-100 rechromatography. The molecular weight of the lipase is estimated to be 45,000 and the isoelectric point to correspond to pH 4.3. pH optimum of action of the purified enzyme, areas of its pH- and thermostability have been determined.

[Application of the ultrafiltration method to the isolation of cholesterol oxidase of microbial origin]. / Primenenie ul'trafil'tratsionnogo metoda dlia vydeleniia kholesterinoksidazy mikrobnogo proiskhozhdeniia.

Ultrafiltration of solutions of intracellular cholesterol oxidase of Actinomyces lavendulae through semi-permeable membranes (N-vinyl pyrrolidone and methacrylate copolymers) of varying porosity and acetyl cellulase ultrafilter UAM-200 M was investigated. The ultrafiltration through membranes of both types involved both concentration and purification of cholesterol oxidase from low molecular weight protein admixtures. When copolymer membranes were used, their performance and degree of purification were higher and losses were lower than in case of UAM-200 M filter. The optimum hydrolytic mode of ultrafiltration of intracellular cholesterol oxidase through both filters was determined.

[Conditions for isolation of cholesterol oxidase from Actinomyces lavendulae mycelia]. / Izuchenie uslovii vydeleniia kholesterinoksidazy iz mitseliia Actinomyces lavendulae.

The isolation conditions, composition and certain properties of cholesterol oxidase from the mycelium Actinomyces lavendulae were studied. Selective extraction of the enzyme occurred upon the mycelium extraction by the Tween-80 containing buffer. The specific activity of cholesterol oxidase thus obtained exceeded seven-fold that of the enzyme isolated via other methods. The optimal concentration of the detergent upon extraction was 0.15%. By disc-electrophoresis it was demonstrated that the preparation isolated from disrupted cells contained, in addition to cholesterol oxidase, 16 other protein components that had no enzymatic activity whereas the Tween-80 extracted preparation included no more than 7 fractions. The study of the relationship between activity of the resultant cholesterol oxidase and the substrate concentration and pH demonstrated that optimal conditions for the enzyme action were at pH 7.0-7.5 and cholesterol oxidase concentration of 0.0316 mM.

[Physiochemical properties of LIA-0191 A and B antibiotics]. / Fiziko-khimicheskie svoistva antibiotikov LIA-0191 A i B.

An antifungal antibiotic LIA-0191 was isolated from the mycelium by methanol extraction. It was shown with thin-layer chromatography that it consisted of components A and B. Component A was isolated with collumn chromatography on silica gel, recrystalization from the solvent mixture as a monocomponent crystalline substance. On the basis of the physicochemical and biological properties it was identified with sentacidin. Component B was obtained from preparation LIA-0191 by the method of counter-current distribution and recrystalization from methanol. Comparison of its physico-chemical and biological properties with those of the known purines and pyrimidine pyrrol showed that antibiotic LIA-0191 B is new.

[Isolation of lipase of microbial origin]. / Vydelenie lipazy mikrobnogo proiskhozhdeniia.

By gel chromatography and polyacrylamide gel disc-electrophoresis the component composition of the culture liquid separated from the mycelium was investigated. After elution from Sephadex G-75 column lipase activity was concentrated in one peak. Out of 13 electrophoretic mobile protein components only one split trioleate. The paper describes a method to isolate lipase from the native solution of the produced which involves enzyme precipitation at 40% saturation of the native solution with ammonium sulphate, dialysis of the resultant concentrate and selective sorption of pigment and protein admixtures on the cellulose anion exchanger. The method maker it possible to obtain a highly purified lipolytic enzyme with a specific activity of up to 15 000 lu/mg protein and to provide its 35--40% yield.

[Comparative study of the properties of lipase of microbial origin]. / Sravnitel'noe izuchenie svoistv lipaz mikrobnogo proiskhozhdeniia

A comparative study of properties of lipases of microbial origin has shown that the pH optimum of the enzymes from Geotrichum asteroides and Penicillium sp. is at pH 7.5 and 5.0, respectively. Lipase from Geotrichum asteroides appears more resistant to high temperatures and pH changes than the enzyme from Penicillium sp. Both enzymes split selectively vegetable oils, especially cotton and sunflower oils. Na cholate and deoxycholate at a concentration of 0.05-0.4% act as hydrolysis activators, particularly with respect to Geotrichum lipase. Na dehydrocholate does not show this effect.

[Isolation and physicochemical characteristics of antibiotics from the LIA-0773 and LIA-0780 s trains]. / Vydelenie i fiziko-khimicheskaia kharakteristika antibiotikov iz shtammov LIA-0773 i LIA-0780

Individual components of the antibiotics from strains LIA-0773 and LIA-0708 were isolated with the method of counter-current distribution. Physico-chemical and biological properties of these substances were studied. It was shown that the substances differed from each other and chondamycin, and antifungal antibiotic by the values of their chromatographic mobility, physico-chemical and biological properties.