Further studies on ASN-136 and monoketo-organomycin cystaurimycin, a broad spectrum substance produced by partial enzymic digestion of monoketo-organomycin.

The two antibiotics ASN-136 and monoketo-organomycin (MKOM) showed very close similarities in their UV, IR spectra and elemental analysis to those of tuberactinomycin and yazumycin respectively. Further chemical and enzymic studies revealed the novelty of the two former antibiotics. Partial enzymic hydrolysis of MKOM yielded a hydrolytic product of more potent inhibitory action compared with the parent antibiotic. Having cystine as the N-terminus and taurine as the C-terminus in its molecule, this enzymic degradation product was designated cystaurimycin. Performic acid oxidation of MKOM and of cystaurimycin improved their growth inhibitory effects on the test organisms used.