2-Thioflavins as active site probes of flavoproteins.
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چکیده
منابع مشابه
2-Thioflavins as active site probes of flavoproteins.
4-Thioflavins (oxygen at position 4 replaced by sulfur) have been studied as potential active site probes of flavoproteins. They react readily with thiol reagents, with large spectral changes, which should be useful for testing the accessibility of the flavin 4-position in flavoproteins. They have an oxidation-reduction potential at pH 7 of -0.055 V, approximately 0.15 V higher than that of nat...
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The chemical reactivity of 8-chloroflavins and 8-mercaptoflavins has been exploited in order to examine the orientation of protein-bound flavins relative to solvent. The apoprotein form of a series of flavoproteins was prepared and the native flavin was replaced by either 8-C1-flavin or 8-mercaptoflavin (FAD, FMN, or riboflavin form as was appropriate). The reconstituted proteins were exposed t...
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6-Thiocyanatoflavins have been found to be susceptible to nucleophilic displacement reactions with sulfite and thiols, yielding respectively the 6-S-SO3--flavin and 6-mercaptoflavin, with rate constants at pH 7.0, 20 degrees C, of 55 M-1 min-1 for sulfite and 1000 M-1 min-1 for dithiothreitol. The 6-SCN-flavin binds tightly to riboflavin-binding protein as the riboflavin derivative, to apoflavo...
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Flavin enzymes are unique as biological catalysts in that they carry out a wide variety of different biochemical processes. This sets them apart from enzymes which use other coenzymes, like pyridine nucleotides, pyridoxal phosphate or thiamin pyrophosphate, each of which involves a single type of chemical event. Flavins thus are involved in the dehydrogenation of a variety of substrates, in one...
متن کامل8-Mercaptoflavins as active site probes of flavoenzymes.
Representative examples of the various classes of flavoproteins have been converted to their apoprotein forms and the native flavin replaced by 8-mercapto-FMN or 8-mercapto-FAD. The spectral and catalytic properties of the modified enzymes are characteristically different from one group to another; the results suggest that flavin interactions at positions N(1) or N(5) of the flavin chromophore ...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1982
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)68343-2