Reaction: dihydroceramide + NADPH + H+ + O2 => phytoceramide + NADP+ + H2O
- in pathway: Sphingolipid de novo biosynthesis
DEGS2 (sphingolipid C4-hydroxylase 2 / “degenerative spermatocyte homolog 2”) enzyme associated with the cytosolic face of the endoplasmic reticulum catalyzes the hydroxylation of dihydroceramide to form phytoceramide (Mizutani et al. 2004). Sequence similarity to the bifunctional mouse DEGS2 enzyme suggests that human DEGS2 protein might also catalyze the C4-dehydrogenation of dihydroceramide, but this hypothesis has not been tested experimentally.
Reaction - small molecule participants:
H2O [cytosol]
NADP+ [cytosol]
N-acylphytosphingosine [endoplasmic reticulum membrane]
H+ [cytosol]
DHCE [endoplasmic reticulum membrane]
O2 [cytosol]
NADPH [cytosol]
Reactome.org reaction link: R-HSA-428260
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Reaction input - small molecules:
hydron
N-acylsphinganine
dioxygen
NADPH(4-)
Reaction output - small molecules:
water
NADP(3-)
N-acylphytosphingosine
Reactome.org link: R-HSA-428260