[Search for actinomycetes that produce inhibitors of proteolytic enzymes].

The inhibiting activity of filtrates of the cultural broth against trypsin and chymotrypsin was studied among 66 actinomycetes. The highest activity against trypsin was found, after selection, in the following cultures: Act. janthinus 118, Act. violatus 125, Act. violaceus confinus 2476, Act. violaceus vicinus 1074. The antitrypsin activity was detected in the cultural broth of Act. janthinus 118 during the first day of its growth, and reached maximum by the third day. The inhibiting substance in the cultural broth is thermo- and pH-stable, is not extracted with organic solvents, and remains in the bag during dialysis. Apparently, the inhibitor (s) of trypsin produced by Act. janthinus 118 differes from trypsin inhibitors of microbial origin and low molecular weight which have been described so far.