Effects of proteinase inhibitors on the differentiation process of physarum flavicomum : isolation of proteinases from growing and encysting cells
The use of several inhibitors of proteinases has revealed the inhibition by some and delay by others of the differentiation process of Physarum flavicomum haploid cells. Among these inhibitors TLCK was the first (inhibiting encystment in both SD medium and BS solution) and antipain (inhibiting encystment in SD medium) the second most effective inhibitor of the encystment process. Chloroquine was also a potent inhibitor preventing differentiation in SD medium. Leupeptin, pepstatin and the growth factor hemin all delayed the encystment process in SD medium. The proteinases were isolated from growing cells, and cells that had started to differentiate (5% cysts) in SD medium, by affinity chromatography. All of the inhibitors were tested for the inhibitory effects upon the crude extract from both growing and differentiating cells of P. flavicomum in SD medium using Azocoll and Azocasein as subtrate. All inhibitors were found to be effective in blocking part of the proteolytic activity of the crude extract with different ranges. For each inhibitor the inhibition was found to be concentration dependent.