Nozaki Y, Kawashima F, Imada A
J Antibiot (Tokyo). 1981 Feb;34(2):206-11. doi: 10.7164/antibiotics.34.206.
Biochemical activities of new carbapenem antibiotics, C-19393 H2(H2) and C-19393 S2(S2), were examined in comparison with those of mecillinam using Escherichia coli. H2 showed remarkably high affinity for penicillin-binding protein (PBP) 2, and high affinity for PBPs 1 and 3. S2 showed high affinity for PBP 2, moderate affinity for PBP 1 and low affinity for PBP 3. They induced ovoid cells at lower concentrations and cell lysis at higher concentrations. The inhibitory potency of H2 for peptidoglycan synthesis was similar to that of mecillinam at lower concentrations up to 0.1 micrograms/ml. At concentrations higher than 0.1 micrograms/ml, the inhibition rate by H2 gradually increased up to 100%, whereas that by mecillinam remained at 60% level. The MICs of H2, S2 and mecillinam corresponded to the lowest concentrations giving 60% of inhibition of peptidoglycan synthesis at which concentrations the function of PBP 2 seemed to be prevented completely. These findings indicate that the primary targets of H2 and S2 are PBP 2 involved in cell shape determination in E. coli.
使用大肠杆菌，对新型碳青霉烯类抗生素C-19393 H2（H2）和C-19393 S2（S2）的生化活性与美西林进行了比较研究。H2对青霉素结合蛋白（PBP）2表现出极高的亲和力，对PBPs 1和3也有高亲和力。S2对PBP 2表现出高亲和力，对PBP 1有中等亲和力，对PBP 3有低亲和力。它们在较低浓度时诱导形成卵形细胞，在较高浓度时导致细胞裂解。在浓度高达0.1微克/毫升时，H2对肽聚糖合成的抑制效力与美西林相似。在高于0.1微克/毫升的浓度下，H2的抑制率逐渐增加至100%，而美西林的抑制率则保持在60%的水平。H2、S2和美西林的最低抑菌浓度（MIC）对应于肽聚糖合成抑制率达60%时的最低浓度，在该浓度下PBP
