Streptomyces rimosus extracellular proteases

Summary A trypsin-like proteinase was isolated from Streptomyces rimosus culture filtrates obtained from an oxytetracycline production process. The isolation procedure includes ultrafiltration, chromatography on CM-Sephadex, AH-Sepharose and CM-cellulose and gives a homogeneous protein with 19% yield. The enzyme is an anionic trypsin (M_r 28 000, pI 4.5), is stable from pH 4.5 to 9 and up to 40°C, and contains three disulphide bridges, three histidines and three methionines per molecule. At its pH optimum (pH 8.4–8.8) it splits peptide, ester and arylamide bonds of arginine in the endo-position and, to a smaller extent, in the exo-position. Like other streptomycete trypsins, it is a more efficient catalyst than bovine trypsin and has a relative preference for peptide-arylamides, N-benzyloxycarbonyl-l-norleucyl-l-prolyl-l-arginine-p-nitroanilide being by far its best substrate.