THERMITASE - A THERMOSTABLE SERINE PROTEASE .6. KINETIC AND FLUORESCENCE STUDIES ON THE INTERACTION OF THE ENZYME WITH DANSYLATED PEPTIDE CHLOROMETHYL KETONES

  • 1 January 1984
    • journal article
    • research article
    • Vol. 43  (7) , 909-918
Abstract
The modification of thermitase with dansylated peptide chloromethyl ketones Dns-Alann-PheCH2 (n = 1-4) was investigated by means of kinetic and fluorescence methods. The influence of dimethyl formamide and dimethyl sulfoxide on the enzyme activity is reported. The synthesis of the Dns-substituted chloromethyl ketones acting as irreversible inhibitor was started from the analogous Z-compounds. The substances Dns-Alan-PheCH2Cl with n = 1, 2 and 3 have lower inhibition effects than the sequence homologous Z-protected peptide chloromethyl ketones. The fluorescence measurements showed that the dansyl group forms hydrophobic interactions with the enzyme and takes part in energy transfer processes particularly in the case of thermitase labeled with Dns-Ala2-PheCH2Cl. From the kinetic data of the DNA- and Z-protected inhibitors thermitase presents 5 subsites at the S-sites of its active center. The topology of the active center of thermitase is comparable with that of subtilisin BPN''.

This publication has 1 reference indexed in Scilit: