Synthesis of biological precursors of cholic acid II
摘要:
This paper describes the partial syntheses of 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-al, 7 alpha, 12 alpha, 26-trihydroxy-5 beta-cholestan-3-one and 7 alpha, 12 alpha-dihydroxy-3-oxo-5 beta-cholestan-26-al via Ag2CO3/Celite oxidation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 26-tetrol. These bile alcohols were resolved by analytical and preparative TLC, characterized by gas-liquid chromatography and mass spectrometry. These compounds will be useful to delineate further the mechanism of oxidation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol on the pathway to cholic acid.
This paper describes the partial syntheses of 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-al, 7 alpha, 12 alpha, 26-trihydroxy-5 beta-cholestan-3-one and 7 alpha, 12 alpha-dihydroxy-3-oxo-5 beta-cholestan-26-al via Ag2CO3/Celite oxidation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 26-tetrol. These bile alcohols were resolved by analytical and preparative TLC, characterized by gas-liquid chromatography and mass spectrometry. These compounds will be useful to delineate further the mechanism of oxidation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol on the pathway to cholic acid.
Putative Helix F Contributes to Regioselectivity of Hydroxylation in Mitochondrial Cytochrome P450 27A1
作者:Irina A. Pikuleva、Andrei Puchkaev、Ingemar Björkhem
DOI:10.1021/bi010193i
日期:2001.6.1
correctly oriented substrate to the P450 active site. The I211K and F215K mutations, for example, affected the regioselectivity of P450 27A1-dependent hydroxylation reactions and conferred the P450 capacity to cleave the C-C bond of the substrate during the catalytic cycle. Studies of P450 11A1 indicate that Phe-202 has functions similar to those of its counterpart in P450 27A1 (Phe-215). We propose that