title: Biosynthesis of leupeptin. IV. Is protein turnover in leupeptin producer cells affected by leupeptin?
abstract: There was no significant difference between the rates of protein degradation in cells of a leupeptin-producing strain and that of a leupeptin-nonproducing strain, the latter being derived from the former by mutation. Protein autodigestion in a cell homogenate of the leupeptin producer was sensitive to EDTA and chymotrypsin and less sensitive to leupeptin. On the contrary, protein degradation caused by exogenous trypsin in a similar homogenate was highly sensitive to leupeptin. A labeling experiment with [14C]-arginine of a culture of the leupeptin producer strain revealed that leupeptin was accumulated mostly in the medium and only slightly in the cells; the ratio between the amount in the medium and that in the cells was about 250:1. In contrast, leupeptin acid, the proximal intermediate having no antiplasmin activity, showed a ratio of 5:1.
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001711:Biotransformation; D002478:Cells, Cultured; D007976:Leupeptins / Q000096:biosynthesis*; D009842:Oligopeptides / Q000096:biosynthesis*; D011480:Protease Inhibitors / Q000494:pharmacology; D013302:Streptomyces / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D007976:Leupeptins; D009842:Oligopeptides; D011480:Protease Inhibitors