Abstract: | 1. Susceptibility to inhibitors of neutral protease from calf thymus chromatin has been compared with that of trypsin. The chromatin protease reacts stoichiometrically with the inhibitors specific for trypsin (diisopropylfluorophosphate, tosyl-lysyl chloromethane, soybean trypsin inhibitor and Kunitz basic inhibitor from pancreas), but not with the inhibitor specific for chymotrypsin (tosyl-phenylalanyl chloromethane). 2. Chromatin protease, similarly as trypsin, cleaves Lys-X and Arg-X peptide bonds. 3. It is concluded that the structure of active site region of both enzymes is very similar. |