منابع مشابه
Crystal structure of human uroporphyrinogen III synthase.
Uroporphyrinogen III synthase, U3S, the fourth enzyme in the porphyrin biosynthetic pathway, catalyzes cyclization of the linear tetrapyrrole, hydroxymethylbilane, to the macrocyclic uroporphyrino gen III, which is used in several different pathways to form heme, siroheme, chlorophyll, F(430) and vitamin B(12). U3S activity is essential in all organisms, and decreased activity in humans leads t...
متن کاملPurification and properties of uroporphyrinogen III synthase from human erythrocytes.
Uroporphyrinogen III synthase (hydroxymethylbilane hydro-lyase (cyclizing); EC 4.2.1.75), the fourth enzyme in the heme biosynthetic pathway, was purified to homogeneity from human erythrocytes. For enzyme purification and characterization, a sensitive coupled enzyme assay was used which generated the substrate, hydroxymethylbilane; the oxidized product, uroporphyrin III, was quantitated by hig...
متن کاملPhylogenetic analysis of uroporphyrinogen III synthase (UROS) gene
The uroporphyrinogen III synthase (UROS) enzyme (also known as hydroxymethylbilane hydrolyase) catalyzes the cyclization of hydroxymethylbilane to uroporphyrinogen III during heme biosynthesis. A deficiency of this enzyme is associated with the very rare Gunther's disease or congenital erythropoietic porphyria, an autosomal recessive inborn error of metabolism. The current study investigated th...
متن کاملOrder of uroporphyrinogen III decarboxylation on incubation of porphobilinogen and uroporphyrinogen III with erythrocyte uroporphyrinogen decarboxylase.
The isomeric compositions of the heptacarboxylic, hexacarboxylic and pentacarboxylic porphyrinogens formed by incubation of porphobilinogen with human red-cell haemolysates have been analysed and compared with those derived from incubation with chemically prepared uroporphyrinogen III as substrate. The results indicated that when supplied with an excess (3.7 microM) of exogenous uroporphyrinoge...
متن کاملStructure and mechanistic implications of a uroporphyrinogen III synthase-product complex.
Uroporphyrinogen III synthase (U3S) catalyzes the asymmetrical cyclization of a linear tetrapyrrole to form the physiologically relevant uroporphyrinogen III (uro'gen III) isomer during heme biosynthesis. Here, we report four apoenzyme and one product complex crystal structures of the Thermus thermophilus (HB27) U3S protein. The overlay of eight crystallographically unique U3S molecules reveals...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2000
ISSN: 0021-9258
DOI: 10.1074/jbc.275.4.2295