In vitro antitumor activity of polymyxin acylase from Pseudomonas sp. M-6-3.

Polymyxin acylase from Pseudomonas sp. M-6-3 can deacylate not only polymyxin group antibiotics, but also the long-chain fatty acyl group of proteins and peptides. We found the in vitro antitumor activity of polymyxin acylase against murine and human tumor cells, especially KB cells. The mechanism of the antitumor activity remains equivocal, but we speculate that it may result from the affinity of polymyxin acylase for long-chain fatty acyl proteins in human carcinoma cells.