The omega- and (omega-1)-hydroxylase activities of prostaglandins A1 and E1 and lauric acid by pig kidney microsomes and a purified kidney cytochrome P-450.

Okita, Richard T.; Parkhill, Linda; Yasukochi, Yukio; Masters, Bettie Sue Siler; Theoharides, Anthony D.; Kupfer, David

doi:10.1016/s0021-9258(19)69109-x

Cited by 73 publications

(2 citation statements)

References 28 publications

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“…Studies by Orrenius and co-workers (Jakobsson et al, 1970;Ellin et al, 1972Ellin et al, ,1973 presented no compelling evidence for the involvement of distinct cytochromes P450 in the o>-vs (o> -l)-hydroxylation of lauric acid. However, later experiments in our laboratory by Okita et al (1981) not only suggested that distinct cytochromes P450 were involved in these regioselective activities but also showed that the prostanoids, PGEi and PGAi, could be substrates for these enzymes in porcine kidney microsomal fractions. Following the report of Powell and Solomon (1978) and Powell (1978) that a gestational age dependent w-hydroxylation, inhibitable by carbon monoxide, of prostaglandins and thromboxane B2 occurs in the lungs of pregnant rabbits, our laboratory (Williams et al, 1984) and that of Kusunose (Yamamoto et al, 1984) reported the isolation and purification of a cytochrome P450 from lung microsomes capable of catalyzing the oj-hydroxylation of prostaglandins Ei and Ai.…”

Section: Discussionmentioning

confidence: 99%

Cytochrome P450 4A4: Expression in Escherichia coli, purification, and characterization of catalytic properties

Nishimoto¹,

Clark²,

Masters³

1993

Biochemistry

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Rabbit lung prostaglandin omega-hydroxylase (P450 4A4) was expressed in Escherichia coli using the isopropyl beta-D-thiogalactopyranoside (IPTG) inducible expression vector pCWori+, containing the full-length cDNA encoding the P450 4A4. The first seven codons were changed to reflect E. coli codon bias [a modification of the method of Barnes et al. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 5597-5601]; only the second residue of P450 4A4 was altered (Ser to Ala), while the remaining mutations were silent. This strategy was adopted in order to minimize changes in the structure of the expressed enzyme. Induction by IPTG of the apoprotein peaked after 6 h, and by including the heme precursor delta-aminolevulinic acid, enzymatic activity peaked 12 h after addition of IPTG. The isolated membrane fraction, free of cell debris, contained 12-15 nmol of P450/L of media. The expressed enzyme was purified to electrophoretic homogeneity, and kinetic and spectrophotometric data indicate that this expressed, purified enzyme is equivalent to the enzyme purified from rabbit lung. The Km for PGE1 was determined to be 3.0 microM, which is the same as that obtained for the enzyme purified from lung [Williams et al. (1984) J. Biol. Chem. 259, 14600-14608]. The CO-reduced difference spectrum of purified P450 4A4 exhibited a lambda max at 450 nm, and the absolute absorbance spectrum of the pyridine hemochromogen revealed a typical b type heme. To characterize P450 4A4 further, the catalytic activities with prostaglandin E1 (PGE1), arachidonate, 15-hydroxyeicosatetraenoic acid (15-HETE), and palmitate were investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 99%

Cytochrome P450 4A4: Expression in Escherichia coli, purification, and characterization of catalytic properties

Nishimoto¹,

Clark²,

Masters³

1993

Biochemistry

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“…To date, only a small number of cytochrome P-450 isozymes have been purified from livers of untreated animals (Schenkman et al, 1982;Kamataki et al, 1983;Ryan et al, 1984). These native forms of cytochrome P-450 are of great interest in view of the fact that they may be involved in the metabolism of endogenous substrates such as vitamin D (Hansson et al, 1981), testosterone (Ryan et al, 1982b; Cheng & Schenkman, 1983; Harada & Negishi, 1984), progesterone (Johnson et al, 1983; Cheng & Schenkman, 1984), estradiol (Johnson et al, 1983; Cheng & Schenkman, 1984), prostaglandins (Okita et al, 1981;Vatsis et al, 1982), fatty acids (Gibson et al, 1980;Tamburini et al, 1984), andcholesterol (Waxman, 1986). In this manner, such P-450 isozymes may play a significant role in regulation of the metabolism of a variety of natural compounds important to normal cellular metabolism.…”

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confidence: 99%

Cytochrome P-450 C-M/F, new constitutive form of microsomal cytochrome P-450 in male and female rat liver with estrogen 2- and 16.alpha.-hydroxylase activity

Sugita

Sassa²,

Miyairi³

et al. 1988

Biochemistry

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A new cytochrome P-450 isozyme, P-450C-M/F, has been purified from untreated rat liver microsomes. The purified preparation was electrophoretically homogeneous and contained 12-15 nmol of P450/mg of protein and had a minimum molecular weight of 48,500. The NH2-terminal amino acid sequence of P-450C-M/F was different from that of other P-450's. Immunoblot analysis of microsomes demonstrated that P-450C-M/F was present in the liver of untreated male as well as female rats. Treatment of rats with phenobarbital, 3-methylcholanthrene, or beta-naphthoflavone did not induce P-450C-M/F. Cytochrome P-450C-M/F exhibited little activities of 7-ethoxycoumarin and 7-ethoxyresorufin O-deethylation or hydroxylation of arylhydrocarbon, testosterone, androstenedione, and progesterone. In contrast, it was highly active in N-demethylation of ethylmorphine and benzphetamine and in 2- and 16 alpha-hydroxylation of estrogens, particularly that of estradiol. These studies establish that cytochrome P-450C-M/F is constitutively present in both male and female rats and suggest that it may be involved in the oxidative metabolism of estradiol, particularly in the formation of estriol, the uterotropic metabolite of estradiol.

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Prostanoid Metabolism and Biologically Active Product Formation

Kupfer¹

1991

Molecular Aspects of Monooxygenases and Bioactivation of Toxic Compounds

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The omega- and (omega-1)-hydroxylase activities of prostaglandins A1 and E1 and lauric acid by pig kidney microsomes and a purified kidney cytochrome P-450.

Cited by 73 publications

References 28 publications

Cytochrome P450 4A4: Expression in Escherichia coli, purification, and characterization of catalytic properties

Cytochrome P450 4A4: Expression in Escherichia coli, purification, and characterization of catalytic properties

Cytochrome P-450 C-M/F, new constitutive form of microsomal cytochrome P-450 in male and female rat liver with estrogen 2- and 16.alpha.-hydroxylase activity

Prostanoid Metabolism and Biologically Active Product Formation

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