Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The dominant position among oxidoreduction processes in peroxisomes is ascribed to catalase, a number of aerobic oxidases, and Cu,Zn-superoxide dismutase. The peroxidase reaction of catalase requires substrates for hydrogen donation, other than H2O2, e.g. alcohols, aldehydes, formic acid. The peroxisomes contain an alternative system of beta-oxidation of higher carboxylic acids which in some types of plant cells is functionally very closely associated with the glyoxylate cycle. Regarding the role of peroxisomes in the metabolism of carboxylic acids, a very important finding has taken place, namely that besides acyl-CoA synthetase which is specific for long chains, the peroxisomes contain still another enzyme which allows the synthesis of CoA esters of fatty acids with very long chains. It is assumed that the entry of acyl-CoA esters or fatty acids into the perxisomes is performed by means of pores in membranes or acyl-carnitine transferases. Peroxisomes oxidize a very wide scale of substrates and contain several types of acyl-CoA oxidases: palmitoyl-CoA oxidase, pristanoyl-CoA oxidase, trihydroxy-coprostanoyl-CoA oxidase. The second and third reactions of peroxisomal beta-oxidation are catalyzed by the so-called three-functional enzyme, the activities of which are identical to those of 2-enoyl-CoA hydratase, beta-hydroxyacyl-CoA dihydrogenase and enoyl-CoA isomerase. The peroxisomes sufficiently oxidize dicarboxylic acids with a higher number of carbons beginning with the adipic acid. The peroxisomal system of beta-oxidation is utilized in metabolism of prostaglandins, pristanic acid-being the product of phytanic acid alpha-oxidation, and cholesterol. Several enzymatic activities needed for the synthesis of cholesterol partially take place in peroxisomes. The peroxisomes represent a decisive compartment for the initial phases of synthesis of plasmalogens. They contain the following enzymes: NAD(+)-glycerol-P-dehydrogenase, dihydroxyacetone-3-P-acyl-transferase, alkyl-dihydroxyacetone-P synthetase and acyl/alkyl-dihydroxyacetone-P reductase. The metabolism of amino acids takes place under the effect of peroxisomal enzymes--oxidase of diamino acids, D-aspartate oxidase, oxidase of L-pipecolic acid and alanine-glyoxylate aminotransferase. Only a few published sources consider it obvious that liver peroxisomes participate in degradation of spermine and spermidine. Polyamine oxidase oxidizes spermine resulting in the origin of spermidine and 3-aminopropionaldehyde, and spermidine is oxidized to putrescine and 3-aminopropionaldehyde. Peroxisomes in many phylogenetically lower animal species enable the break down of purine bases to urea and glyoxylic acid. In phylogenetically higher primates and in man, the activities of urate oxidase in peroxisomes are absent. (Fig. 14, Ref. 166).
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PMID:The role of peroxisomes in intermediary metabolism. 855 58

Peroxisomal beta-oxidation is involved in the degradation of different fatty acids or fatty acid derivatives including eicosanoids (prostaglandins, leukotrienes, thromboxanes), dicarboxylic fatty acids, very long-chain fatty acids, pristanic acid, bile acid intermediates (di- and trihydroxycoprostanoic acids), and xenobiotics. Separate beta-oxidation systems are probably active inside peroxisomes, each acting on a distinct set of substrates, as suggested by the discovery of multiple acyl-CoA oxidases. Using specific substrates or selective conditions, we can distinguish in rat liver the action of acyl-CoA oxidases (type I and II), a pristanoyl-CoA oxidase and a trihydroxycoprostanoyl-CoA oxidase, and, in in human liver, of acyl-CoA oxidase (type I and II) and a branched-chain acyl-CoA oxidase. When incubated with suitable CoA-esters, these different oxidases can be measured in a similar fashion by following fluorimetrically the dimerization of homovanillic acid, catalysed by peroxidase in the presence of hydrogen peroxide. The optimal assay conditions and possible pitfalls in this type of coupled assay are discussed. This knowledge can be used to reveal the existence of peroxisomal disorders in which only one acyl-CoA oxidase is deficient.
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PMID:Activity measurements of acyl-CoA oxidases in human liver. 905 47

Because of the 2S-methyl-stereospecificity of the acyl-CoA oxidases acting on the CoA esters of 2-methyl-branched fatty carboxylates such as pristanic acid and the side chain of trihydroxycoprostanic acid (Van Veldhoven P.P., Croes K., Asselberghs S., Herdewijn P. and Mannaerts G.P. (1996) FEBS Lett. 388, 80-84), naturally occurring 2R-pristanic acid and 25R- (corresponding to 2R in the side chain) trihydroxycoprostanic acid, after activation to their CoA-esters, need to be racemized to the S-isomers before they can be degraded by peroxisomal beta-oxidation. A coupled assay to measure 2-methyl-acyl racemases was developed by using purified rat pristanoyl-CoA oxidase. Upon incubation of rat and human liver homogenates with 2R-methyl-pentadecanoyl-CoA, the formed 2S-methyl isomer was desaturated by an excess of added oxidase and the concomitant production of hydrogen peroxide was monitored by means of peroxidase in the presence of a suitable hydrogen donor. Application of this assay to subcellular fractions of rat liver revealed the presence of racemase activity not only in mitochondria, as described by Schmitz W., Albers C., Fingerhut R. and Conzelmann E. (Eur. J. Biochem. (1995) 231, 815-822), but also in peroxisomes and cytosol. A similar distribution was seen in human liver. In rat the highest activities were found in liver, followed by Harderian gland, kidney and intestinal mucosa.
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PMID:2-methylacyl racemase: a coupled assay based on the use of pristanoyl-CoA oxidase/peroxidase and reinvestigation of its subcellular distribution in rat and human liver. 923 87