Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.44 (AGT)
 770 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

Male pseudohermaphroditism due to 5 alpha-reductase deficiency was clinically and biochemically described in a large Dominican kindred of 23 families with 38 affected subjects in 1974. Recently, the 5 alpha-reductase-2 gene defect in the large Dominican kindred was found to be due to a single base substitution of thymidine (TGG) for cytosine (CGG) on exon 5 of the 5 alpha-reductase-2 gene, causing a tryptophan replacement of arginine at amino acid 246 (R246W) of the enzyme. In the present report, affected subjects from four additional Dominican families were studied to determine whether they carried the same 5 alpha-reductase-2 gene defect as the large kindred, suggesting a common ancestry for the gene defect within this small country. Using single strand conformational polymorphism and DNA sequencing, two other mutations of the 5 alpha-reductase-2 gene were found in affected subjects from two of the four families. A point mutation on exon 2 of the 5 alpha-reductase-2 gene, in which substitution of adenine (GAC) for guanine (GGC) caused an aspartic acid replacement of glycine at amino acid 115 (G115D), was demonstrated in one of these families, and a substitution of adenine (AGT) for guanine (GGT) on exon 3 causing a serine replacement for glycine at amino acid 183 (G183S) was detected in the other family. Affected subjects from the two remaining families demonstrated the same exon 5 mutation of the 5 alpha-reductase-2 gene as previously detected in the large Dominican kindred. The phenotypic and biochemical characteristics of the male pseudohermaphrodites were similar regardless of the genetic defect, except that one affected subject (C-VI-2) with the same exon 5 mutation as the large Dominican kindred had much more facial and body hair. Thus, the identification of multiple mutations in the 5 alpha-reductase-2 gene in male pseudohermaphrodites from the Dominican Republic demonstrates a lack of common ancestry, as had been previously postulated.
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PMID:5 alpha-reductase-2 gene mutations in the Dominican Republic. 862 25