Preparation and properties of des-Tyr98 and des-Arg97-Tyr98 acylphosphatase (muscular isoenzyme).

摘要: Previous NMR reports indicated that Tyr98, the C-terminal residue of muscular form acylphosphatase, is likely to be part enzyme's active site. In addition, there evidence an arginine participates catalyzed reaction, possibly as phosphate binding Among all Arg residues present in forms four, i.e. Arg23, Arg74, Arg77, and Arg97, appear conserved species checked thus far. We prepared des-Tyr98 des-Arg97-Tyr98 derivatives native acylphosphatase investigate properties both modified enzymes. The enzyme lacking Tyr98 was found catalytically less effective than one, whereas completely inactive. This suggests Arg97 directly site catalytic mechanism. Fluorescence CD spectra revealed latter could have been undergone some conformational change account for loss activity; on other hand, one-dimensional either enzymes were strictly similar, demonstrating removal two does not markedly affect fold enzyme. results reported are proof a critical contribution site; however, we cannot exclude function this merely stabilize conformation dynamics.