3-keto-steroid reductase; Responsible for the reduction of the keto group on the C-3 of sterols; Belongs to the short-chain dehydrogenases/reductases (SDR) family. ERG27 subfamily.

Lanosterol 14-alpha demethylase; A cytochrome P450 monooxygenase involved in sterol biosynthesis. Catalyzes 14-alpha demethylation of lanosterol and 24,25- dihydrolanosterol likely through sequential oxidative conversion of 14- alpha methyl group to hydroxymethyl, then to carboxylaldehyde, followed by the formation of the delta 14,15 double bond in the sterol core and concomitant release of formic acid. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P45 [...]

Squalene monooxygenase; Catalyzes the stereospecific oxidation of squalene to (S)- 2,3-epoxysqualene, and is considered to be a rate-limiting enzyme in steroid biosynthesis.

Lathosterol oxidase; Catalyzes a dehydrogenation to introduce C5-6 double bond into lathosterol.

Lanosterol synthase; Catalyzes the cyclization of (S)-2,3 oxidosqualene to lanosterol, a reaction that forms the sterol nucleus. Through the production of lanosterol may regulate lens protein aggregation and increase transparency.

Squalene synthase; Critical branch point enzyme of isoprenoid biosynthesis that is thought to regulate the flux of isoprene intermediates through the sterol pathway; Belongs to the phytoene/squalene synthase family.

7-dehydrocholesterol reductase; Production of cholesterol by reduction of C7-C8 double bond of 7-dehydrocholesterol (7-DHC).

Hydroxymethylglutaryl-CoA synthase, cytoplasmic; This enzyme condenses acetyl-CoA with acetoacetyl-CoA to form HMG-CoA, which is the substrate for HMG-CoA reductase.

Diphosphomevalonate decarboxylase; Performs the first committed step in the biosynthesis of isoprenes; Belongs to the diphosphomevalonate decarboxylase family.