Concentration on Diapak C 16 capsules of lovastatin, mevinolinic acid and other inhibitors of biosynthesis of sterins produced by Penicillium citrinum 89]

The method of lovastatine and mevinolinic acid known as competitive inhibitors of HMG-CoA-reductase and produced by micromycetes was elaborated. The inhibitors from diluted water solutions were fully absorbed on Diapak C16 patrons. The rate of inhibitors elution from the patrones was more than 95 per cent. Patrons may be used for concentration of lovastatine group inhibitors from the culture media. Inhibitors synthesis by the Penicillium citrinum 89 was investigated in dynamics with the use of Diapak C16 patrones. It was shown that UV-spectrum of inhibitor produced by P. citrinum 89 was identical with compactin spectrum and had absorbance maximum at 230, 237 and 247 nm.     

Interaction of N1-, N6- and C8-substituted derivatives of adenosine-5'-triphosphate with the catalytic subunit of cAMP-dependent protein kinase from rabbit skeletal muscles

In order to investigate the structure of the active site of the cAMP-dependent protein kinase catalytic subunit a synthesis of several previously unknown adenosine-5'-triphosphate (ATP) derivatives containing substituents of various nature at N(1), N(C6) and C(8) positions of the purine base was carried out. The interaction of these derivatives with a homogeneous preparation of the catalytic subunit of rabbit skeletal muscle cAMP-dependent protein kinase was investigated. All the nucleotide analogs were found to inhibit the enzyme activity; the inhibition was competitive with respect to ATP. It was assumed that the adenine moiety of the ATP molecule is bound to the active site of protein kinase by the hydrophobic interaction with the aromatic amino acid residues and by formation of the hydrogen bond between the exo-NH2-group of the substrate and a corresponding group of the enzyme. The "correct" binding of ATP to the enzyme active center is defined by the anti-conformation of the nucleotide.     

Conditions for nisin adsorption by Streptococcus lactis cells

Some conditions for absorption of nisin, a polypeptide antibiotic by the cells of Str. lactis were studied. The amounts of nisin adsorbed by the cells depended on the culture age: at the late stationary phase the adsorption level was 2 times higher than that at the logarithmic phase. The cells grown on a "poor" medium adsorbed 85-90 per cent of nisin added to the solution, while the cells grown on the "rich" medium adsorbed 50 per cent of the antibiotic. The adsorption level of nisin by the cells subjected to a thermal shock was higher than that by the live cells. Desorption of nisin from the cells with acid ethanol and bivalent cation solutions was insignificant. Nisin is adsorbed by the cells of other microorganisms, the adsorption levels by the cells of Bac. brevis being the same as those by the streptococcal cells, while the levels adsorbed by Bac. polymyxa being 4 times lower.     

Inorganic phosphate is used for synthesis of phosphatidylinositol-4,5-diphosphate

It was shown that exogenous inorganic phosphate can be incorporated into newly synthesized phosphatidylinositol-4,5-bisphosphate without any participation of ATP.