Conversion of Aspartate Aminotransferase into anl-Aspartate β-Decarboxylase by a Triple Active-site Mutation
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چکیده
منابع مشابه
Acylation of aspartate aminotransferase.
1. Acetylation of aspartate aminotransferase from pig heart inhibits completely the enzymic activity when the coenzyme is in the amino form (pyridoxamine phosphate) or when the coenzyme has been removed, but not when the coenzyme is in the aldehyde form (pyridoxal phosphate). 2. The group the acylation of which is responsible for the inhibition has been identified with the in-amino group of a l...
متن کاملPhotoinactivation of aspartate aminotransferase.
The cofactor pyridoxal 5’-phosphate bound through an aldimine linkage to lysine residues of the enzyme aspartate amiuotransferase is very stable to irradiation with light of 420 nm. The catalytic function of the enzyme exposed to light absorbed by the cofactor remains unaffected, indicating that pyridoxal 5’-phosphate is not an efficient active site photosensitizer for this aminotransferase. Th...
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Aspartate: 2-oxoglutarate aminotransferase from the anaerobic protozoon Trichomonas vaginalis was purified to homogeneity and characterized. It is a dimeric protein of overall Mr approx. 100000. Only a single isoenzyme was found in T. vaginalis. The overall molecular and catalytic properties have features in common with both the vertebrate cytoplasmic and mitochondrial isoenzymes. The purified ...
متن کاملA spin label substrate analogue as active site-directed modifying agent. Tryptophan 140 of aspartate aminotransferase.
The interaction of cytoplasmic aspartate aminotransferase with the spin probe substrate analogue potassium nitrosodisulfonate (NDS) has been investigated using the a-subform of the pig heart enzyme. Electron paramagnetic resonance studies show that NDS binds to the enzyme. Scatchard plots with different concentrations of NDS are linear and show the presence of two binding sites/dirner (KO = 0.7...
متن کاملCoenzyme active site occupancy as an indicator of independence of the subunits of mitochondrial aspartate aminotransferase.
The enzyme, aspartate aminotransferase, is a dimer consisting of two identical subunits which contain overlapping subunit regions ( Eichele , G., Ford, G.C., Glor , M., Jansonius , J.N., Mavrides , C., and Christen , P. (1979) J. Mol. Biol. 133, 161-180), suggesting the possibility of subunit interactions. The structurally similar cytosolic isozyme exhibits noncooperative binding of pyridoxal 5...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1999
ISSN: 0021-9258
DOI: 10.1074/jbc.274.44.31203