In
enzymology
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
, a sterol 24-C-methyltransferase () is an
enzyme that
catalyzes
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
the
chemical reaction
:S-adenosyl-L-methionine + 5alpha-cholesta-8,24-dien-3beta-ol
S-adenosyl-L-homocysteine + 24-methylene-5alpha-cholest-8-en-3beta-ol
Thus, the two
substrates of this enzyme are
S-adenosyl methionine and
5alpha-cholesta-8,24-dien-3beta-ol, whereas its two
products are
S-adenosylhomocysteine and
24-methylene-5alpha-cholest-8-en-3beta-ol.
This enzyme belongs to the family of
transferases, specifically those transferring one-carbon group methyltransferases. The
systematic name of this enzyme class is S-adenosyl-L-methionine:zymosterol 24-C-methyltransferase. Other names in common use include Delta24-methyltransferase, Delta24-sterol methyltransferase, zymosterol-24-methyltransferase, S-adenosyl-4-methionine:sterol Delta24-methyltransferase, SMT1, 24-sterol C-methyltransferase, S-adenosyl-L-methionine:Delta24(23)-sterol methyltransferase, and phytosterol methyltransferase. This enzyme participates in
biosynthesis of steroids
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; a ...
. It employs one
cofactor,
glutathione.
References
*
*
*
*
*
EC 2.1.1
Enzymes of unknown structure
{{2.1-enzyme-stub