A second CYP26 P450 in humans and zebrafish: CYP26B1

Arch Biochem Biophys. 1999 Nov 15;371(2):345-7. doi: 10.1006/abbi.1999.1438.


A new P450 gene has been found in humans. It has 44% sequence identity to CYP26A1 from human and mouse, which places it in a new subfamily, CYP26B. There is only one human EST from a retinal library (AA012833) that matches the coding region. No homologous ESTs are found in mouse. A zebrafish EST AI721901 shows 68% identity to the human protein. This zebrafish EST is only 41% identical to the zebrafish CYP26A1 protein sequence, so it represents the homolog of the human CYP26B1 sequence. It is not known if this gene product will act on all-trans-retinoic acid like the CYP26A1 protein or if it might hydroxylate the 9-cis- or 13-cis-retinoic acid isoforms not recognized by CYP26A1. The importance of the CYP26A1 P450 in mouse and zebrafish development flags the CYP26B1 gene as a potential developmental gene.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chromosome Mapping
  • Cytochrome P-450 Enzyme System / genetics*
  • Expressed Sequence Tags
  • Humans
  • Isoenzymes / genetics
  • Molecular Sequence Data
  • Retinoic Acid 4-Hydroxylase
  • Sequence Homology, Amino Acid
  • Zebrafish
  • Zebrafish Proteins


  • Isoenzymes
  • Zebrafish Proteins
  • Cytochrome P-450 Enzyme System
  • CYP26B1 protein, human
  • Cyp26a1 protein, mouse
  • Cyp26b1 protein, mouse
  • Retinoic Acid 4-Hydroxylase
  • cyp26a1 protein, zebrafish

Associated data

  • GENBANK/AC007002
  • GENBANK/U68234