Human glutathione reductase (NADPH + GSSG + H+ in equilibrium with NADP+ + 2 GSH) is a suitable enzyme for correlating spectroscopic properties and chemical reactivities of protein-bound FAD analogues with structural data. FAD, the prosthetic group of the enzyme, was replaced by FAD analogues, which were modified at the positions 8, 1, 2, 4, 5 and 6, respectively, of the isoalloxazine ring. Whe...

The native flavin, FAD, of spinach ferredoxin--NADP+ reductase, has been replaced by a number of FAD analogues with modifications of the isoalloxazine ring system. The apoenzyme binds 8-mercapto-FAD in its thiolate anion form and 6-hydroxy-FAD in its neutral form. These results are consistent with classification of this enzyme as a dehydrogenase/electron transferase, an ascription originally ma...

The compound 5-((2-aminoethylamino)methyl)-7-(4-bromoanilino)-3-cyano-pyrazolo[1,5-a]pyrimidine (ABCPP) was synthesized and conjugated with N-mercapto-acetylglycine (MAG), N-mercaptoacetylphenylalanine (MAF) and N-mercaptoacetylvaline (MAA), respectively. These three compounds were labeled successfully with [99mTcN]2+ intermediate in high radiochemical purities. Biodistribution in tumor-bearing...

ABSTRACT. A novel series of antipyrinyl thienyl ketones 4a-c, 7a-c, 10a-c, and 13a-b was chemically synthesized through the cyclocondensation 4-chloroacetylantipyrine with various 2-substituted-thioacetanilide scaffolds, including 3-arylazo-4-mercapto-4-phenylamino-buten-2-ones, ethyl 2-arylazo-3-mercapto-3-phenylamino-acrylate, 2-cyano-3-mercapto-3-(phenylamino)-N-arylacrylamide, 4-mercapto-4-...

Shiga toxin 1 (Stx1) catalyses the removal of a unique and specific adenine from 28S RNA in ribosomes (RNA-N-glycosidase activity) and the release of multiple adenines from DNA (DNA glycosylase activity). Added adenine behaves as an uncompetitive inhibitor of the RNA-N-glycosidase reaction binding more tightly to the Stx1-ribosome complex than to the free enzyme. Several purine derivatives and ...

Combinatorial chemistry was used to extend the knowledge of beer thiols by synthesizing 13 mercapto primary alcohols and 6 other compounds (mercapto ketones and corresponding alcohols). Their respective mass spectra, retention indices on two columns, odor descriptors, and best estimated-gas chromatography-lowest amounts detected sniffing (BE-GC-LoADS) are reported. The descriptor "cheese", comm...