title: The isomerization catalyzed by Brevibacterium sterolicum cholesterol oxidase proceeds stereospecifically with one base.
abstract: We have demonstrated that the isomerization reaction catalyzed by Brevibacterium sterolicum (ATCC 81387) cholesterol oxidase (EC 1.1.3.6) proceeds via a stereospecific proton transfer from the 4 beta carbon to the 6 beta carbon to form 4-cholestene-3-one using deuterated and nondueterated substrates. This result implies that there is one active site base, positioned over the beta-face, responsible for isomerization. On the basis of X-ray crystallographic evidence [Li, J., Vrielink, A., Brick, P. & Blow, D. M. Biochemistry 32, 11507-11515 (1993)], glutamate-361 is the most likely candidate for this general base.
authors: Department of Chemistry, State University of New York at Stony Brook 11794-3400.
authors: I J
authors: IJ
authors: Kass
authors: N S
authors: NS
authors: Sampson
mesh_terms: D001951:Brevibacterium / Q000201:enzymology*; D002783:Cholestenones / Q000737:chemistry / Q000378:metabolism; D002789:Cholesterol Oxidase / Q000378:metabolism*; D007536:Isomerism; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D002783:Cholestenones; D002789:Cholesterol Oxidase