Properties of three proteinases functioning at G1, S and G2 phases in HeLa cells and their inhibition by guanidino- and amidino-acid esters.

HeLa cells were synchronized by double thymidine-block and allowed to grow after removal of thymidine. Three proteinases, tryptase 17:17, proteinase In and late G2 proteinase, were prepared from the HeLa cells harvested at the time when each proteinase appeared in the cell cycle of the cells. All of them were suggested to be trypsin-like serine proteinases, because they hydrolyzed trypsin-specific fluorogenic substrates and their activities were inhibited by benzamidine, soybean trypsin inhibitor, leupeptin, tosyl-L-lysine chloromethan (TLCK) and diisopropylfluorophosphate (DEP). However, the actions of these proteinases on the substrates and inhibitors suggested that they were three different proteinases. They were strongly inhibited by 4-tert-butylphenyl and biphenyl esters of trans-4-guanidinomethylcyclohexanecarboxylic acid, amidinopiperidine-4-acetic and 4-propionic acids, which retard the second DNA synthetic (S) and mitotic (M) phases for 3h, 4-tert-butylphenyl ester of amidinopiperidin-4-carboxylic acid, which blocks initiation of S phase, the ester of amidinopiperidine-4-butyric acid, which suppresses the second S and M phases, and the esters of trans-4-amidinocyclohexanecarboxylic and 4-propionic acids which inhibit M phase.