2007;282:5225C5236. lacking the hepatic or renal enzyme entirely. CYP4F2 content material in liver microsomes was significantly correlated (r 0.63; p < 0.05) with leukotriene B4 and arachidonate -hydroxylase activities, which are both CYP4F2-catalyzed. Our study provides the 1st example of a peptide antibody that recognizes a single CYP4F P450 indicated in human being liver and kidney, namely CYP4F2. Immunoquantitation and correlation analyses performed with this antibody suggest that CYP4F2 functions like a predominant LTB4 and arachidonate -hydroxylase in human being liver. Keywords: CYP450, CYP4F2, fatty acids, eicosanoids, -hydroxylation, peptide antibodies Intro P450 enzymes comprise a superfamily of hemoproteins that oxidize both xenobiotics and endobiotics, including medicines, environmental pollutants, steroid hormones, and fatty acids. While most study on P450 enzymes offers focused on their capacity to metabolize restorative providers [1, 2], more attention is being paid to the endobiotic-metabolizing properties of these enzymes, of which many belong to the and gene subfamilies [3, 4]. Indeed, the human being CYP4F/A enzymes have been shown to: a) function as catalysts of medium-, long-, and very long-chain fatty acid -hydroxylation [5C7], which facilitates the decreasing of excessive free fatty acid levels; b) convert one particular fatty acid, AA, into the potent eicosanoid 20-HETE [8C10], a powerful vasoconstrictor, inhibitor of ion transport and cellular proliferation agent; c) catabolize numerous AA oxygenated derivatives, including leukotrienes (e.g., LTB4), prostaglandins, and lipoxins, therefore inactivating these bioactive lipid mediators [11C17]. VRT-1353385 CYP4F-mediated rate of metabolism of another endogenous substrate, namely vitamin E, represents the initial step in this compounds biotransformation [18, 19]. In contrast to additional P450s, the CYP4F/A proteins possess the unique ability to oxidize, or -hydroxylate, the thermodynamically-unfavorable terminal methyl group present on saturated and unsaturated fatty acids of different chain lengths, AA-derived eicosanoids, and tocopherol phytyl part chains. Considering their catalytic properties, Robo3 it is not surprising the CYP4F/A enzymes are thought to play an important part in the rules of particular physiological and/or pathological phenomena. Indeed, potential relationships have been explained between CYP4A and CYP4F protein levels and/or connected metabolic activities and the amplitude of LTB4-dependent inflammatory processes [20 and recommendations therein], blood pressure rules [21], and cellular proliferation [22]. However, the task of a specific CYP4F gene subfamily P450 to a particular endobiotic-metabolizing activity VRT-1353385 occuring in undamaged tissue has verified problematic. While CYP4A11 constitutes the solitary, major CYP4A P450 indicated in human being liver and kidney, at least 4 unique CYP4F P450s are abundantly indicated in these same cells. In fact, the human being CYP4F gene subfamily is definitely comprised of 6 different users, including CYP4F2, CYP4F3a, CYP4F3b, CYP4F8, CYP4F11 and CYP4F12, which possess 74% overall amino acid sequence homology. CYP4F2, CYP4F3b, CYP4F11 and CYP4F12 are found in liver and kidney [10, 16, 23C25] whereas CYP4F3a is found only in myeloid cells [26, 27] and CYP4F8 is definitely expressed specifically in seminal vesicles [28]. CYP4F3a and CYP4F3b have identical amino acid sequences except at VRT-1353385 residues 67C114, where option exon splicing offers led to the integration of exon 3 into CYP4F3b and exon 4 into VRT-1353385 CYP4F3a. Such alternate exon splicing gives two P450 enzymes with markedly different substrate specificity and cells distribution [10, 16]. Several of the above findings, including CYP4F2 involvement in hepatic and renal 20-HETE formation and LTB4 catabolism [8, 9, 15], were arrived at using CYP4F2-reactive polyclonal antibodies as metabolic probes2. The considerable sequence homology found among the CYP4F P450s predicts, however, that our initial polyclonal CYP4F2 antibodies reacted not only with their immunogen but also with the additional CYP4F subfamily users now known to be expressed in human being liver and kidney. A similar phenomenon, namely antibody cross-reactivity among the users of a P450 gene subfamily, was observed with antibodies elicited against human being liver CYP2C9 [29]. As such, it is possible that CYP4F enzymes other than CYP4F2, such as CYP4F3b, CYP4F11 or CYP4F12, also function as catalysts of fatty acid and LTB4 -hydroxylation. Indeed, CYP4F3b.