Ground-State Electronic Destabilization via Hyperconjugation in Aspartate Aminotransferase
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چکیده
منابع مشابه
Ground-state electronic destabilization via hyperconjugation in aspartate aminotransferase.
Binding isotope effects for l-aspartate reacting with the inactive K258A mutant of PLP-dependent aspartate aminotransferase to give a stable external aldimine intermediate are reported. They provide direct evidence for electronic ground-state destabilization via hyperconjugation. The smaller equilibrium isotope effect with deazaPLP-reconstituted K258A indicates that the pyridine nitrogen plays ...
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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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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...
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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 ...
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The activity of aspartate aminotransferase (AST) in human serum has been widely determined as a diagnostic aid in liver disease. In this study, the effect of aluminium on AST isoenzymes in relation to aluminium intoxified patients has been investigated. Using gel filtration chromatography technique with Sephacryl S-300, mitochondrial aminotransferase (m-AST) and cytosolic aminotransferase (c-AS...
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ژورنال
عنوان ژورنال: Journal of the American Chemical Society
سال: 2012
ISSN: 0002-7863,1520-5126
DOI: 10.1021/ja302809e