ExplorEnz: EC 1.14.19.17

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1.14.19.17

Accepted name:

sphingolipid 4-desaturase

Reaction:

a dihydroceramide + 2 ferrocytochrome b₅ + O₂ + 2 H⁺ = a (4E)-sphing-4-enine ceramide + 2 ferricytochrome b₅ + 2 H₂O

Glossary:

a dihydroceramide = an N-acylsphinganine

Other name(s):

dehydroceramide desaturase

Systematic name:

dihydroceramide,ferrocytochrome b₅:oxygen oxidoreductase (4,5-dehydrogenating)

Comments:

The enzyme, which has been characterized from plants, fungi, and mammals, generates a trans double bond at position 4 of sphinganine bases in sphingolipids [1]. The preferred substrate is dihydroceramide, but the enzyme is also active with dihydroglucosylceramide [2]. Unlike EC 1.14.19.29, sphingolipid 8-desaturase, this enzyme does not contain an integral cytochrome b₅ domain [4] and requires an external cytochrome b₅ [3]. The product serves as an important signalling molecules in mammals and is required for spermatide differentiation [5].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc

References:

1.	Stoffel, W., Assmann, G. and Bister, K. Metabolism of sphingosine bases. XVII. Stereospecificities in the introduction of the 4t-double bond into sphinganine yielding 4t-sphingenine (sphingosine). Hoppe-Seylers Z. Physiol. Chem. 352 (1971) 1531–1544. [PMID: 5140816]
2.	Michel, C., van Echten-Deckert, G., Rother, J., Sandhoff, K., Wang, E. and Merrill, A.H., Jr. Characterization of ceramide synthesis. A dihydroceramide desaturase introduces the 4,5-trans-double bond of sphingosine at the level of dihydroceramide. J. Biol. Chem. 272 (1997) 22432–22437. [DOI] [PMID: 9312549]
3.	Causeret, C., Geeraert, L., Van der Hoeven, G., Mannaerts, G.P. and Van Veldhoven, P.P. Further characterization of rat dihydroceramide desaturase: tissue distribution, subcellular localization, and substrate specificity. Lipids 35 (2000) 1117–1125. [DOI] [PMID: 11104018]
4.	Ternes, P., Franke, S., Zähringer, U., Sperling, P. and Heinz, E. Identification and characterization of a sphingolipid Δ⁴-desaturase family. J. Biol. Chem. 277 (2002) 25512–25518. [DOI] [PMID: 11937514]
5.	Michaelson, L.V., Zäuner, S., Markham, J.E., Haslam, R.P., Desikan, R., Mugford, S., Albrecht, S., Warnecke, D., Sperling, P., Heinz, E. and Napier, J.A. Functional characterization of a higher plant sphingolipid Δ⁴-desaturase: defining the role of sphingosine and sphingosine-1-phosphate in Arabidopsis. Plant Physiol. 149 (2009) 487–498. [DOI] [PMID: 18978071]

[EC 1.14.19.17 created 2015]