Transient State Kinetic Investigation of 5-Aminolevulinate Synthase Reaction Mechanism
نویسندگان
چکیده
منابع مشابه
Pre-steady-state reaction of 5-aminolevulinate synthase. Evidence for a rate-determining product release.
5-Aminolevulinate synthase (ALAS) is the first enzyme of the heme biosynthetic pathway in non-plant eukaryotes and the alpha-subclass of purple bacteria. The pyridoxal 5'-phosphate cofactor at the active site undergoes changes in absorptive properties during substrate binding and catalysis that have allowed us to study the kinetics of these reactions spectroscopically. Rapid scanning stopped-fl...
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The mechanistic pathway for the reaction catalyzed by Kdo8P synthase has been investigated, and the cyclic bisphosphate 2 has been examined as a putative reaction intermediate. Two parallel approaches were used: (1) chemical synthesis of 2 and evaluation as an alternate substrate for the enzyme and (2) transient kinetic studies using rapid chemical quench methodology to provide direct observati...
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cDNA clones for rat liver 5-aminolevulinate synthase have been isolated and used to examine mRNA levels in different rat tissues. Northern hybridization analysis of total RNA from various rat tissues showed the presence of a single 5-aminolevulinate synthase mRNA species of estimated length 2.3 kilobases. Primer extension and RNase mapping studies indicated that the mRNA is identical in all tis...
متن کاملMode of binding of pyridoxal phosphate to 5-aminolevulinate synthase.
5-Aminolevulinate synthase of Rhodopseudomonas spheroides interacts with its cofactor, pyridoxal phosphate, and shows an absorption maximum at 430 nm with a probable shoulder at 320--330 nm. The enzyme-PLP complex absorbing at 430 nm is the predominant species at pH 7.2 and can be reduced by NaBH4 at neutral pH with a spectral shift of the absorption maximum to 325 nm. These data suggests the f...
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Different cytochromes P450 are involved in steroid biosynthesis. These cytochromes have heme as the prosthetic group. We previously reported that ACTH, an activator of glucocorticoid biosynthesis in adrenal, requires heme biosynthesis for a maximal response. In the present study, we investigated the effect of ACTH, and the effect of two activators of the adrenal mineralocorticoid synthesis, end...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2002
ISSN: 0021-9258
DOI: 10.1074/jbc.m203584200