Partial purification and some properties of a bovine brain trypsin inhibitor.
Using hemoglobin modified by pyridoxal 5'-phosphate as substrate, a trypsin inhibitor from bovine brain was purified by extraction at pH 4.5, ion-exchange chromatography on DEAE-Sephadex A-50, gel filtration on Sephadex G-100 and isoelectric focusing. On a column of Sephadex G-100 the inhibitor exhibited a molecular mass of 78 kDa. The iso-electric point of the inhibitor was 4.3-4.4. The dissociation constant (Ki) for the complex of bovine trypsin and brain inhibitor was estimated to be 3.7 X 10(-10)M as tested with a protein substrate, and 2.4 X 10(-10)M when tested with a synthetic substrate. During purification two other brain trypsin inhibitors were detected.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D002540:Cerebral Cortex / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D008970:Molecular Weight; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000032:analysis / Q000302:isolation & purification*
D014361:Trypsin Inhibitors; D014357:Trypsin