Phenol 2monooxygenase

Oestrone is a substrate in rat and hamster A2408, C896, G625 . A human enzyme hydroxylates 17p-oestradiol at the 7a-position A2465 . The same reaction is observed in rat A1487, A2192 . Oestrone is a substrate in rat and hamster A2408, C896, G625 . A human enzyme hydroxylates 17b-oestradiol at the 7b-position A2465 . This activity is found in Neurospora, with 17b-oestradiol as substrate A944 . Rat liver micromes hydroxylate 17b-oestradiol and oestriol at the 14a-position H342 . A...

MHydroxybenzyl alcohol 6hydroxylase

M -Hydroxybenzyl alcohol 6-hydroxylase Penicilliun patulum microsomal enzyme, optimum pH 7.5, requires NADPH in the formation of gentisyl alcohol. It is suggested that the enzyme is m -cresol 2-hydroxylase A2314 . 2, 3-dihydroxybenzoate (pyrocatechuate) Rat liver enzyme is considered to act via a free radical that non-specifically causes hydroxylation of salicylate rather than by the action of a hydroxylase J754 . Rat liver enzyme is considered to act via a free radical that non-specifically...

LDopachrome tautomerase

D-dopachrome into 5,6-dihydroxyindole. The enzyme source is not clear from Chemical Abstracts it is claimed to be a rat enzyme, but it may be the same as that described in another publication, found in human lymphocytes. The latter is a macrophage migration inhibition factor in addition to its tautomerase activity J475, J514 . L-Dopachrome tautomerase (E C. 5.3.3.12) Mouse melanoma enzyme forms 5,6-dihydroxyindole-2-carboxylate as the initial product. The apoenzyme is activated by Zn2 + , but...

Anthranilate 5hydroxylase

Purified enzyme also catalyzes the formation of pyrocatechuate, which suggests that it also shows anthranilate 2,3-hydroxylase (deaminating) activity (E.C. 1.14.13.35) it is claimed that both activities reside on the same molecule. Cu2+ and p -chloromercuribenzoate are inhibitory D231 . This reaction is also observed in rat liver and brain A3653, F676 . This reaction is observed in rat liver A3653, D296 . Indole 4-hydroxylase is found in pumpkin A3530 . A similar reaction occurs...

Oxidations and reductions involving the aromatic nucleus and nonorganic substituents

2.1 Hydroxylation of the aromatic nucleus 2.1.1 Hydroxylations associated with physiologically important amino acids and hormones Phenylalanine hydroxylase (phenylalanine 4-monooxygenase E.C. 1.14.16.1) This vertebrate enzyme degrades dietary phenylalanine in excess of requirements for protein and hormone formation. In a group of closely associated inherited diseases in man (e.g. phenylketonuria, hyperphenylalaninaemia) that result in moderate to severe mental retardation, this enzyme is either...

Formation and degradation of sidechains

Human bone marrow supplemented with S-adenosylmethionine converts benzene into toluene, which in turn yields o -, m - and p -xylenes F853 . This may account for the apparent hydroxymethylation of benzene (Sloane, N.H., Biochim. Biophys. Acta (1965), 107, 599 Sloane, N.H., Heinemann, M., Biochim. Biophys. Acta (1970), 201, 384). Rat is able to incorporate a methyl group at positions 7 and 12 of benzanthracene and possibly its metabolites. Incorporation was not observed with a range of...

Benzophenone synthase

Absent, there must be a suspicion that the preparations were all contaminated with this enzyme. Benzophenone synthase (E.C. 2.3.1.151) Centaurium erythraea enzyme, optimum pH 7.5, acts on m -hydroxybenzoyl CoA and malonyl CoA to form 2,3',4,6-tetrahydroxybenzophenone J35 . Aspergillus parasiticus converts hexanoate or pentanoate into norsolorinate, a polyphenolic anthraquinone, which is a postulated precursor of aflatoxin Bi. With pentanoate, an additional reaction product with a 5-oxopentane...

Rcocooh 0 Rcho

The reaction has been found in Bragyrhizobium elkanii J189 , E. coli H348 and Azospirillum lipoferum F49 . Enterobacter cloacae enzyme has been reviewed K792 . Indole-3-pyruvate ferredoxin oxidoreductase Pyrococcus furiosus enzyme is a tetramer composed of two pairs of subunits, molecular weights 23 000 and 66 000, optimum pH 8.5-10.5, with one thiamine, a cluster of 4 4Fe-4S 2 + '1 + and one 3Fe-4S 0,1+ units, and a requirement for CoA. The products from indole-3-pyruvate, phenylpyruvate and p...

RCH30 rch2oh

Rat liver enzyme oxidizes 7-methyl- and 7,12-dimethylbenzanthracene, incorporating oxygen from molecular oxygen, but not from water A339 . A Pseudomonas putida enzyme, which acts on 4-hydroxy-3-methylbenzoate is a 2-protein system, molecular weight 115 000, that appears to be composed of a flavin-containing hydroxylase and an electron-transfer system that uses NADH. It is claimed to be an unusual type of mixed-function oxidase F223 . The electron transfer system appears to be a flavocytochrome...

Rchohcooh 0 Rcocooh

Rhodotorula graminis l-( )-mandelate dehydrogenase is a tetramer, monomeric molecular weight 59 100, that contains one mol each of haem and FMN per subunit. The optimum pH is 7.9, and pI 4.4. It acts on mandelate and a series of nuclear-substituted analogues H90 and is stereospecific G904 . Both d- and l-dehydrogenases are inducible. l-Dehydrogenase, optimum pH 7.0, requires dichlorophenolindophenol as reductant, and may be membrane-bound activity is enhanced by phenazine methosulphate....

Tyramine 3hydroxylase

Ascorbate activates, and diethyldithiocarbamate is inhibitory A541 . Berberis stolonifera phenoloxidase, molecular weight 60 000 and optimum pH 6.0, oxidizes both l-tyrosine and tyramine, as well as some phenolic tetrahydroisoquinoline natural products. Both ascorbate and oxygen are required for activity F855 . Horseradish peroxidase and peroxide act on mixtures of dopa and phenols the phenols accelerate the oxidation of dopa, although when the phenol used is...

Peptide tryptophan 23dioxygenase

Wheat germ optimum pH about 8 and rat liver enzymes act on tryptophan residues in polypeptides such as pepsin and trypsin, converting them into kynurenine residues K823 . Indole 2,3-dioxygenase E.C. 1.13.11.17 In rat, indole is converted into N-formylanthranilate, which is the expected initial product of indole ring fission, as well as anthranilate D158 . Jasminum grandiflorum leaf enzyme, optimum pH 4.8, forms anthranilate from the substrate. Other substrates are 5-hydroxy- and 5-bromoindole....

Hydroxylation by monophenol monooxygenase

A manner similar to beef brain enzyme see below A3017 . Beef corpus striatum enzyme molecular weight about 60 000 is activated by incubation with ATP and cyclic AMP-dependent protein kinase, which yields a phosphorylated hydroxylase containing one mol of phosphate B413 . Caudate nucleus enzyme is activated by phosphatidylserine and other polyanions, which reduce Km for the pterin cofactor. Phosphatidylserine raises the optimum pH from about 6 by 1 unit, whereas the effect of heparin is...

RNO20 rnh2

This reaction often, if not always, involves the formation of intermediate nitroxides and hydroxylamines, although in many studies these intermediates were not detectable. Human placenta reduces p -nitrobenzoate to p-aminobenzoate. Fractionation indicates that Reduction of nitro compounds to anilines the active enzymes are haemoglobin or methae-moglobin. Studies with pure proteins found that the reaction can be catalyzed by haem-containing proteins such as methaemoglobin, metmyoglobin and cytochrome c, with NADPH as reducing agent. Placental reduction and the haem-model system haematin, NADPH, FMN and p -nitrobenzoate are inhibited by carbon monoxide A621 . Formation of p -aminobenzoate from p -nitrobenzoate is observed in conventional rats, but is, relatively, very low in germ-free animals. Studies with microorganisms have found reduction by the gut flora Lactobacillus plantarum, Bacteroides fragilis, Peptostreptococcus productus, Clostridium, Proteus mirabilis, S. faecalis and E....