Studies on Streptomyces griseus protease : II. The amino acid sequence around the reactive serine residue of DFP-sensitive components with esterase activity

Abstract

1. 1. A highly purified esterase preparation from Streptomyces griseus protease (Pronase), active against benzoylarginine ethyl ester, was inactivated with [ 32P]DFP and hydrolysed with HCl. From the acid hydrolysate, the dipeptides Asp-[ 32P]SerP and [ 32P]SerP-Gly, as well as the tripeptide ASp-([ 32P]SerP, Gly), were isolated. This shows that the amino acid sequence around the reactive serine residue of the enzyme is Asp-Ser-Gly. 2. 2. Two other esterase components from Pronase, active against p-nitrophenl acetate, were inactivated with [ 32P]DFP and hydrolysed in the same manner. On paper electrophoresis at pH 3.5, identical patterns of 32P-labelled peptides were obtained from all three enzyme components. This indicates that the three esterases have the same amino acid sequence at the DFP-reacting site.