Hydrolysis of soybean trypsin inhibitor by the gamma subunit of 7SNGF and EGF-BP.
Although soybean trypsin inhibitor (STI) does not inhibit the esterase activity of either epidermal growth factor binding protein (EGF BP) or the gamma subunit of 7SNGF, it does behave as a substrate for proteolysis. Cleavage of the active site peptide bond of STI does occur when incubated in the presence of either EGF-BP or the gamma subunit of 7SNGF. The hydrolysis id pH dependent with maximum proteolysis at pH 6.0-7.0. the newly formed C-terminal arginine residue in modified STI can be released by carboxypeptidase B digestion. Both enzymes are inhibited by low concentrations (2-4 microgram/ml) of the microbial protease inhibitors leupeptin and antipain. These inhibitors are specific for trypsin-like proteases. Since both enzymes can be found as part of high molecular weight complexes with growth factors these results confirm the hypothesis that they are involved during a postranslational modification event.
D000596:Amino Acids / Q000032:analysis; D002352:Carrier Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009414:Nerve Growth Factors; D011956:Receptors, Cell Surface; D013025:Glycine max; D014361:Trypsin Inhibitors
D000596:Amino Acids; D002352:Carrier Proteins; D009414:Nerve Growth Factors; D011956:Receptors, Cell Surface; D014361:Trypsin Inhibitors; D004815:Epidermal Growth Factor; D066246:ErbB Receptors