Neurospora tryptophan synthase. Characterization of the pyridoxal phosphate binding site.
نویسندگان
چکیده
منابع مشابه
Affinity labeling of the pyridoxal phosphate binding site of the beta2 subunit of Escherichia coli tryptophan synthase.
We have synthesized bromoacetylpyridoxamine phosphate and bromoacetylpyridoxamine and have shown that they meet three criteria for affinity labels of the beta2 subunit of tryptophan synthase: (i) the kinetic data of inactivation indicate that a binary complex is formed prior to covalent attachment; (ii) inactivation is largely prevented by the presence of pyridoxal phosphate; and (iii) inactiva...
متن کاملThe Role of Pyridoxal Phosphate in the Aldolytic Activity of Tryptophan Synthetase from Neurospora Crassa.
The formation of tryptophan (Reactions 1 and 2) requires the coenzyme pyridoxal phosphate. According to the proposed mechanism of action of pyridoxal enzymes (3, 4), the aldolyticl activity of tryptophan synthetase (Reactions 3f and 3r) would not be expected to require pyridoxal-P as a coenzyme; yet DeMoss and Bonner (7) reported that the Reaction 3f activity of a mutationally altered tryptopha...
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...
متن کاملInteractions between tryptophan synthase from Escherichia coli and derivatives of the coenzyme pyridoxal 5'-phosphate.
Coenzyme Derivatives, Pyridoxal 5'-Phosphate, Tryptophan Synthase The interaction of the coenzyme analogues pyridoxal (A), pyridoxine 5'-phosphate (B), pyridoxic acid 5'-phosphate (Q and N-phosphopyridoxyl-L-serine (D) with both the isolated apo ß2 subunit and the native <x2 apo ß2 bienzyme complex of tryptophan synthase from Escherichia coli has been investigated using enzyme kinetics and CD s...
متن کاملBinding of Pyridoxal 5'-Phosphate
1. The a and ,B subforms of aspartate aminotransferase were purified from pig heart. 2. The a subform contained 2mol of pyridoxal 5'-phosphate. The apo-(a subform) could be fully reactived by combination with 2mol of cofactor. 3. The protein fluorescence of the apo(a subform) decreased non-linearly with increase in enzyme activity and concentration of bound cofactor. 4. It is concluded that the...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1988
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)68725-3