Biphenyl 4-hydroxylase

Weaver, D.E. and van Lier, R., Coupled P-cyclodextrin and reverse-phase high-performance liquid chromatography for assessing biphenyl hydroxylase activity in hepatic 9000g supernatant, Anal. Biochem., 154, 590, 1986. 

Biphenyl Hydroxylase, Arylhydrocarbon Hydroxylase, and Epoxide Hydrolase... 

Intestinal microsomal metabolism can be monitored via biphenyl hydroxylation as well. Biphenyl hydroxylase assays are more sensitive than some other hydroxylase assays which has permitted measurements of the low constituative enzyme levels in intestinal mucosa and some other extrahepatic tissues (56-59) ... 

Arylhydrocarbon Hydroxylase. Benzo(a)pyrene (BaP) is considered an ideal model compound for monitoring arylhydrocarbon hydroxylase (AAH) MFO levels in rats. Its metabolism has been widely investigated in both rat liver and extrahepatic tissues (40-41,61 -70). Arylhydrocarbon hydroxylase has been compared to biphenyl hydroxylase in the intestines of rats (25,28). Intestinal AAH has been shown to be induced up to 30-fold with cytochrome P-448-type inducers, while being insensitive to P-450-type induction. Therefore, we have used intestinal AAH in conjunction with biphenyl hydroxylation, to evaluate the effects of dietary fibers on intestinal metabolism. 

Table V. Biphenyl Hydroxylase Activities in Liver Microsomes of Fiber-Fed Rats.

Fiber Type Intestine x) Length (cm) Mucosal x) Weight (g) Microsomal x) Protein (mg/g) 2-OH Biphenyl Hydroxylase 3-OH 4- -OH... 

D.E. Weaver, and R.B.L. van Lier, Coupled P- Cyclodextrin and Reversed- Phase High Performance Liquid Chromatography for Assessing Biphenyl Hydroxylase Activity in Hepatic 9000g Supernatant, Anal. Biochem., 5 9%6)A590. 

A cytochrome P450 has been purified from Saccharomyces cerevisiae that has benzo[a]pyrene hydroxylase activity (King et al. 1984), and metabolizes benzo[fl]pyrene to 3- and 9-hydroxybenzo[fl]pyrene and benzo[fl]pyrene-7,8-dihydrodiol (Wiseman and Woods 1979). The transformation of PAHs by Candida Upolytica produced predominantly monohydroxyl-ated products naphth-l-ol from naphthalene, 4-hydroxybiphenyl from biphenyl and 3- and 9-hydroxybenzo[fl]pyrene from benzo[fl]pyrene (Cerniglia and Crow 1981). The transformation of phenanthrene was demonstrated in a number of yeasts isolated from littoral sediments and of these, Trichosporumpenicillatum was the most active. In contrast, biotransformation of benz[fl]anthracene by Candida krusei and Rhodotorula minuta was much slower (MacGillivray and Shiaris 1993). 

Figure 13.21 Mononuclear non-haem iron enzymes from each of the five families in structures which are poised for attack by 02. (a) The extradiol-cleaving catechol dioxygenase, 2,3-dihydroxy-biphenyl 1,2-dioxygenase (b) the Rieske dioxygenase, naphthalene 1,2-dioxygenase (c) isopenicillin N-synthase (d) the ot-ketoglutarate dependent enzyme clavaminate synthase and (e) the pterin-dependent phenylalanine hydroxylase. (From Koehntop et al., 2005. With kind permission of Springer Science and Business Media.)...

Poland, A. and Glover, E. Chlorinated biphenyl induction of arylhydrocarbon hydroxylase activity A study of the structure-activity relationship. Mol. Pharmacol. (1977) 13 924-938. 

Ahmadizadeh M, Kuo C, Echt R, et al. 1984. Effect of polybrominated biphenyls, b-naphthoflavone and phenobarbital on arylhydrocarbon hydroxylase activities and chloroform-induced nephrotoxicity and hepatotoxicity in male C57BL/6J and DBA/2J mice. Toxicology 31 343-352. 

Ah locus A gene(s) controlling the trait of responsiveness for induction of enzymes by aromatic hydrocarbons. In addition to aromatic hydrocarbons such as the polycyclics, the chlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls, as well as the brominated biphenyls, are involved. This trait, originally defined by studies of induction of hepatic aryl hydrocarbon hydroxylase activity following 3-methylcholanthrene treatment, is inherited by simple autosomal dominance in crosses and backcrosses between C57BL/6 (Ah-responsive) and DBA/2 (Ah-nonresponsive) mice. 

Choksi NY, Kodavanti PR, Tilson HA, et al. 1997. Effects of polychlorinated biphenyls (PCBs) on brain tyrosine hydroxylase activity and dopamine synthesis in rats. Fundam Appl Toxicol 39(l) 76-80. 

McCormack KM, Melrose P, Rickert DE, et al. 1979. Concomitant dietary exposure to polychlorinated biphenyls and polybrominated biphenyls Tissue distribution and arylhydrocarbon hydroxylase activity in lactating rats. Toxicol Appl Pharmacol 47 95-104. 

Benzo(a)pyrene hydroxylase activities in hepatic and intestinal microsomes of fiber-fed rats are presented in Table VIII. There were no significant differences (0.05 level) among any of the purified fiber treatment groups in either liver or intestinal microsomes. Lab Chow-fed rats had the lowest liver microsomal benzo(a)pyrene hydroxylase (AHH) level. The indication of enhanced intestinal P-448-dependent hydroxylation of biphenyl in the pectin-fed rats (seen as elevated 3-hydroxybiphenyl formation in microsomes, Table Vl) was not supported by these preliminary data. 

Various conceptual DFT-based reactivity indices in association with some new parameters are successfully employed in the development of stronger QSAR/QSTR models [332]. Deeper correlations of the toxicity of different classes of organic compounds like chlorinated benzenes [333], polychlorinated biphenyls [312, 334—336], and benzidine [337] at DFT level of theory are reported. The toxicity of the polychlorinated biphenyls as well as benzidine is itrfluenced by its electron affinity and planarity. The interactions of the chlorinated benzo-derivatives and benzidine with other biomolecules like nucleic acid/base pairs or aryl hydrocarbon hydroxylase (AHH) receptors are primarily of charge-transfer type, which can be quantitatively assessed from Parr to Pearson formula [254] and can be given as... 

Walters JM, Cain RB, Corner EDS, Higgins IJ (1978) Cell-free benzpyrene hydroxylase activity in marine zooplankton. Proc Soc Gen Microbiol 5 68-69 Walters JM, Cain RB, Higgins IJ (1979a) Increased levels of 3,4-benzopyrene hydroxylase activity in marine zooplankton on exposure to hydrocarbons toxic effect of biphenyl. Proc Soc Gen Microbiol 6 38-39... 

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