EFFECT OF TRANS-4-GUANIDINOMETHYLCYCLOHEXANECARBOXYLIC ACID 4-TERT-BUTYLPHENYL ESTER, A TRYPSIN-INHIBITOR, ON THE GROWTH OF VARIOUS STRAINS OF ESCHERICHIA-COLI

Similarly to Escherichia coli K-12 IAM 1264, trans-4-guanidinomethylcyclohexanecarboxylic acid 4-tert-butylphenyl ester (GMCHA-OPh(t)Bu), a trypsin inhibitor, had a strong inhibitory effect on the growth of various strains of E. coli K-12, such as W 3350, AB 1157, JM 103, W 3110, C 600r-m- and C 600r+m+, preceded by suppressive effects of GMCHA-OPh(t)Bu on DNA synthesis in these strains, although the inhibitory effects varied from strain to strain. These results suggested the possible involvement of a trypsin-like proteinase in DNA synthesis. A trypsin-like proteinase was partially purified from E. coli K-12 AB 1157 by ammonium fractionation and successive chromatographies on DEAE-cellulose, Sephadex G-100 and arginine-Sepharose 4B columns. The properties were compared with those of proteinase In, which instantly appears just before the onset of DNA synthesis and seems to participate in the initiation of DNA replication, and which was purified from E. coli K-12 IAM 1264. The proteinase from E. coli K-12 AB 1157 was identified with proteinase In. These results suggest that proteinase In must be widely distributed in various E. coli strains and plays a pivotal role in the onset of DNA replication.