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CATH Superfamily 3.10.120.10

Cytochrome b5-like heme/steroid binding domain

The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was named:

"
Cytochrome b5-like heme/steroid binding domain
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 21: Delta(8)-fatty-acid desaturase 2

There are 2 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Sphingolipid 8-(E/Z)-desaturase. [EC: 1.14.19.29]
(1) A (4R)-4-hydroxysphinganine ceramide + 2 ferrocytochrome b5 + O(2) + 2 H(+) = a (4R,8E)-4-hydroxysphing-8-enine ceramide + 2 ferricytochrome b5 + 2 H(2)O. (2) A (4R)-4-hydroxysphinganine ceramide + 2 ferrocytochrome b5 + O(2) + 2 H(+) = a (4R,8Z)-4-hydroxysphing-8-enine ceramide + 2 ferricytochrome b5 + 2 H(2)O.
  • The enzymes from higher plants convert sphinganine, 4E-sphing-4-enine and phytosphinganine into E/Z-mixtures of Delta(8)-desaturated products displaying different proportions of geometrical isomers depending on plant species.
  • The nature of the actual desaturase substrate has not yet been studied experimentally.
  • The enzymes contain an N-terminal cytochrome b5 domain that acts as the direct electron donor to the active site of the desaturase.
  • The homologous enzymes from some yeasts and diatoms, EC 1.14.19.18, act on sphing-4-enine ceramides and produce only the trans isomer.
 5 A0A178V7U9 A0A178V7U9 Q3EBF7 Q9ZRP7 Q9ZRP7
Acyl-lipid (8-3)-desaturase. [EC: 1.14.19.30]
(1) An (8Z,11Z,14Z)-icosa-8,11,14-trienoyl-[glycerolipid] + 2 ferrocytochrome b5 + O(2) + 2 H(+) = a (5Z,8Z,11Z,14Z)-icosatetra- 5,8,11,14-tetraenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H(2)O. (2) An (8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoyl-[glycerolipid] + 2 ferrocytochrome b5 + O(2) + 2 H(+) = a (5Z,8Z,11Z,14Z,17Z)-icosa- 5,8,11,14,17-pentaenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H(2)O.
  • The enzyme, which has been characterized from multiple organisms including the moss Physcomitrella patens, the marine microalga Rebecca salina, and the filamentous fungus Mortierella alpina, introduces a cis double bond at the 5-position in 20-carbon polyunsaturated fatty acids incorporated in a glycerolipid that contain a Delta(8) double bond.
  • The enzyme contains a cytochrome b5 domain that acts as the direct electron donor to the active site of the desaturase, and does not require an external cytochrome.
 5 A0A2K1JC31 A0A2K1JC31 A9SIZ6 A9SIZ6 O96099
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