C-8 sterol isomerase activity

Definition

Target type: molecularfunction

Catalysis of the reaction which results in unsaturation at C-7 in the B ring of sterols. [MetaCyc:RXN3O-203, PMID:8988026]

C-8 sterol isomerase activity catalyzes the isomerization of the double bond at position 8 in sterol molecules. This enzymatic activity plays a crucial role in the biosynthesis of sterols, a class of lipids essential for cell membrane structure and function. Specifically, C-8 sterol isomerase converts Δ8-sterols to Δ7-sterols. This isomerization step is critical for the production of cholesterol, a primary sterol in animals, and other important sterols in plants and fungi. The isomerization reaction involves a complex series of proton transfers and hydride shifts that are mediated by the enzyme's active site. The precise mechanism of this reaction remains under investigation, but it is believed to involve a catalytic triad consisting of aspartic acid, histidine, and lysine residues. C-8 sterol isomerase activity is found in a variety of organisms, including bacteria, yeast, plants, and animals. It is an essential enzyme in the biosynthesis of sterols, and its deficiency can lead to various metabolic disorders. For instance, in humans, mutations in the gene encoding C-8 sterol isomerase can cause Smith-Lemli-Opitz syndrome, a rare genetic disorder characterized by severe developmental defects and neurological impairments.'
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Proteins (2)

Compounds (26)