title: Isolation and partial characterization of a low molecular weight acid stable protease inhibitor from human bronchial secretion.
abstract: An acid stable protease inhibitor was isolated from human bronchial secretion. Two important stages of the purification procedure were affinity chromatography on trypsin bound to Affi-Gel 10 and ion-exchange chromatography on SP-Sephadex C-50. The isolated inhibitor appeared as a single band on analytical disc electrophoresis and eluted as a homogeneous protein peak on gel filtration on Sephadex G-75 corresponding to a molecular weight of about 10500. Amino acid analyses showed no tryptophan or histidine and as N-terminal amino acid tyrosine. No glucosamine or galactosamine was detected. The results of the analyses suggest that the purified inhibitor is identical to the low molecular weight trypsin-chymotrypsin inhibitor of human seminal plasma (HUSI-I).
mesh_terms: D001980:Bronchi / Q000201:enzymology / Q000378:metabolism*; D002846:Chromatography, Affinity; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D004355:Drug Stability; D006801:Humans; D008970:Molecular Weight; D011480:Protease Inhibitors; D014361:Trypsin Inhibitors / Q000302:isolation & purification*
chemical_list: D011480:Protease Inhibitors; D014361:Trypsin Inhibitors; D002918:Chymotrypsin