In enzymology, a 3alpha,7alpha,12alpha-trihydroxycholestan-26-al 26-oxidoreductase (EC 1.2.1.40) is an enzyme that catalyzes the chemical reaction
- (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al + NAD+ + H2O (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate + NADH + 2 H+
The 3 substrates of this enzyme are (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al, NAD+, and H2O, whereas its 3 products are (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate, NADH, and H+.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al:NAD+ 26-oxidoreductase. Other names in common use include cholestanetriol-26-al 26-dehydrogenase, 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al, dehydrogenase, trihydroxydeoxycoprostanal dehydrogenase, THAL-NAD oxidoreductase, 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al:NAD+, and 26-oxidoreductase. This enzyme participates in bile acid biosynthesis.