Cloning and expression of a novel form of leukotriene B4 ω‐hydroxylase from human liver

Abstract
We have isolated and sequenced a cDNA for human liver LTB4 ω‐hydroxylase. The cDNA encoded a protein of 520 amino acids with a molecular weight of 59,853 Da. The cDNA‐deduced amino acid sequence showed 87.3% homology to that of human polymorphonuelear leukocytes (PMN) LTB4 ω‐hydroxylase (CYP4F3). Northern blot analysis revealed that the mRNA hybridized to the specific cDNA fragment is expressed in human liver, but not in human PMN. The microsomes from yeast cells transfected with the cDNA catalysed the ω‐hydroxylation of LTB4 with a K m of 44.8 μM. These results clearly show that a new form of the CYP4F LTB4 ω‐hydroxylase exists in human liver.