Tryptophan in the Active Site of Rhodanese

PROBING THE ACTIVE SITE OF RHODANESE WITH DISULFIDE REAGENTS

Studies on the active site of rhodanese.

The complete loss of enzymic activity on reaction with alkylating agents, aromatic nitro compounds, or aliphatic mercaptans indicates the importance of sulfhydryl groups for catalysis. Analyses during the course of inactivation with any of these reagents revealed the loss of one of the two -SH groups in the rhodanese monomer when inactivation was complete. Amino acid analysis of iodoacetate-ina...

probing the active site of rhodanese with disulfide reagents

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Active site structural features for chemically modified forms of rhodanese.

In the course of the reaction catalyzed by rhodanese, the enzyme cycles between two catalytic intermediates, the sulfur-free and the sulfur-substituted (persulfide-containing) forms. The crystal structure of sulfur-free rhodanese, which was prepared in solution and then crystallized, is highly similar to that of sulfur-substituted enzyme. The inactivation of sulfur-free rhodanese with a small m...

Evidence of Tryptophan at or near Active Site of Glucoamylase I of Arthrobotrys amerospora

Arthrobotrysamerospora (ATCC 34468) produced glucoamylase in a semi-synthetic medium containing starch as a sole carbon source. Polyacrylamide gel electrophoresis of crude glucoamylase showed three isoenzymes. They were designated as glu I, glu II and glu III according to their electrophoretic mobility. These iso-glucoamylases were purified by column chromatography using DEAE-Sephadex A-50. The...