[Oxidation of 17alpha,20beta- and 17alpha,20alpha-dihydroxysipregn-4-en-ones--side products of biotransformation of progesterone by recombinant microorganisms expressing cytochrome P45017alpha].

Progesterone biotransformation with recombinant yeast Yarrowia lipolytica E129A15 and Saccharomyces cerevisiae GRF18/YEp5117 alpha expressing bovine adrenocortical cytochrome P45017 alpha yielded 17 alpha-hydroxyprogesterone and two diols, 17 alpha, 20 beta- and 17 alpha, 20 alpha-dihydroxypregn-4-en-3-one. The oxidation of mixtures of the three steroids with chromic acid resulted in the cleavage of 17-20 bonds in the diols with the formation of androst-4-ene-3,17-dione. The biotransformation of pregn-4-ene-20 beta-ol-3-one by means of Y.

[The covalent-sorption reconstitution of steroid hydroxylases].

The effect of covalent immobilization via free amino groups on the catalytic activity of individual components of the cholesterol side-chain cleavage and 11b-steroid hydroxylation systems (adrenodoxin reductase, adrenodoxin, cytochrome P-450scc and cytochrome P-450(11)b) as well as on that of co-immobilized protein complexes. The protein complex formation at different stages of the monooxygenase cycle (i.e.

[Analysis of protein-protein interactions in an enzymatically complete cholesterol hydroxylating system].

The interaction of the cholesterol side chain cleavage system components--adrenodoxin reductase, adrenodoxin, and cytochrome P-450scc was studied, using enzymatic conversion of the high spin form of cytochrome P-450scc to its low spin form and spectrophotometric analysis of various stoichiometric protein mixtures in the presence of pregnenolone and Tween 20. Upon reconstitution of the enzymatically complete system in the presence of NADPH the formation of a ternary protein complex was accompanied by a 2-10-fold increase of the Kd values as compared to the formation of binary adrenodoxin reductase . adrenodoxin and cytochrome P-450 .

[Interaction between cytochrome P-450scc and adrenodoxin in solution under effects of low spin effectors].

The interaction between cytochrome P-450scc and adrenodoxin and cholesterol under effects of low spin effectors (detergents, pregnolone) was studied. The increase in Tween 20 concentration causes a rise in the Kd values for cytochrome P-450scc complexes with adrenodoxin and cholesterol. Both cholesterol and adrenodoxin can convert the low spin form of cytochrome P-450scc obtained by addition of Tween 20 to the high spin form; however, their combined action results in higher values of the spin state index (A393/A418) at final titration points.