Delta14-sterol reductase

Sterol Δ14 - reductase (also: C14 - sterol reductase, C14SR ) are called enzymes in the cholesterol biosynthesis. The enzymes catalyze the hydrogenation of 4,4-dimethyl- 5α -cholesta -8 ,14,24 - trien- 3β -ol, after which 14 - Demethyllanosterin arises. It occurs in most eukaryotes. In man, there are two enzymes delta -14 sterol reductase activity: TM7SF2 (gene name: TM7SF2 ) is in the membrane of the endoplasmic reticulum (ER) located as lamin B receptor (gene name: LBR) is found on the inner membrane of the cell nucleus. In human TM7SF2 is formed mainly in the heart, brain, pancreas, lung, liver, muscle, kidney, ovary, prostate and testis. LBR also seems to be involved in the organization of chromatin and the nucleus import.

C14SR is redundant in cholesterol biosynthesis; Knockout mice without the TM7SF2 gene show normal metabolic values ​​. In contrast, mutations in the LBR gene can have rare genetic diseases such as the Pelger -Huet anomaly or Greenberg dysplasia result.

Catalyzed reaction

NADPH / H ⇔ NADP

4,4-dimethyl- 5α -cholesta -8 ,14,24 - trien- 3β -ol is hydrogenated, it creates 14 - Demethyllanosterin.