ID   1.14.18.6
DE   4-hydroxysphinganine ceramide fatty acyl 2-hydroxylase.
CA   (1) an N-(1,2 saturated acyl)-(4R)-hydroxysphinganine + 2 Fe(II)-
CA   [cytochrome b5] + 2 H(+) + O2 = an N-(2R-hydroxyacyl)-
CA   4R-hydroxysphinganine + 2 Fe(III)-[cytochrome b5] + H2O.
CA   (2) an N-(1,2 saturated very-long-chain fatty acyl)-(R)-4-
CA   hydroxysphingoid base + 2 Fe(II)-[cytochrome b5] + 2 H(+) + O2 =
CA   an N-(2R-hydroxy-very-long-chain fatty acyl)-(R)-4-hydroxysphingoid base
CA   + 2 Fe(III)-[cytochrome b5] + H2O.
CC   -!- The enzyme, characterized from yeast and mammals, catalyzes the
CC       hydroxylation of carbon 2 of long- or very-long-chain fatty acids
CC       attached to (4R)-4-hydroxysphinganine during de novo ceramide
CC       synthesis.
CC   -!- The enzymes from yeast and from mammals contain an N-terminal
CC       cytochrome b5 domain that acts as the direct electron donor to the
CC       desaturase active site.
CC   -!- The newly introduced 2-hydroxyl group has R-configuration. cf.
CC       EC 1.14.18.7.
DR   Q03529, SCS7_YEAST ;
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