Biochem. J. (2002) 363
(297–303) (Printed in Great Britain)
Cloning and expression of two novel pig liver and kidney fatty acid hydroxylases [cytochrome P450 (CYP)4A24 and CYP4A25]
Kerstin LUNDELL1
Division of Biochemistry, Department of Pharmaceutical Biosciences, University of Uppsala, Box 578, S-751 23 Uppsala, Sweden
A new member of the cytochrome P450 (CYP) 4A subfamily (CYP4A21) was recently cloned by PCR from pig liver [Lundell, Hansson, and Wikvall (2001) J. Biol. Chem. 276, 9606–9612]. This enzyme does not catalyse w- or (w-1)-hydroxylation of lauric acid, the model substrate for CYP4A enzymes. Instead, CYP4A21 participates in bile acid biosynthesis in the pig. Extensive studies, primarily conducted to verify the aberrant amino acids found in CYP4A21 within a normally conserved CYP4A motif, revealed that besides CYP4A21 two additional sequences were co-amplified by PCR. These two sequences (designated CYP4A24 and CYP4A25), generated from both pig liver and kidney, were characterized by restriction-enzyme analysis and were subsequently cloned. The deduced amino acid sequences of CYP4A24 and CYP4A25 share extensive sequence identity (97%). Both enzymes, expressed in yeast cells, exhibit w-and (w-1)-hydroxylase activities towards lauric acid and palmitic acid. The positions of the variable regions between CYP4A24 and CYP4A25, which are confined to b-sheets 1 and 4, indicate a possible difference in substrate specificity or regioselectivity. The porcine CYP4A21, CYP4A24 and CYP4A25 enzymes, with an overall identity of 94%, have probably evolved from a common ancestral gene, perhaps in conjunction with species-specific habits.
Key words: CYP4A subfamily, w-hydroxylation, yeast cell expression.
Abbreviations used: chenodeoxycholic acid, 3a,7a-dihydroxy-5b-cholanoic acid; CYP, cytochrome P450.
1e-mail Kerstin.Lundell@farmbio.uu.se
Received 3 September 2001/20 December 2001; accepted 4 February 2002
The Biochemical Society, London ©
2002
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Unofficial 2010 Impact Factor for BJ Energy calculated by dividing the number of times articles published in 2008 and 2009 were cited in 2010 (based on a search of the Web of ScienceSM Thomson Reuters) by the number of articles published in 2008 and 2009.
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