title: Isolation and partial sequence of a Kunitz-type elastase specific inhibitor from marama bean (Tylosema esculentum).
abstract: An isolation procedure utilizing ammonium sulfate fractionation and affinity chromatography was used to purify an elastase inhibitor present in large amounts in marama beans (Tylosema esculentum). The protein appeared to be heterogeneous due to carbohydrate differences, demonstrating two bands on SDS gels with molecular weights of 17.8 kDa and 20 kDa. Partial sequence, derived from mass spectrometry, indicated that the protein is a Kunitz-type inhibitor distinct from other known plant serine protease inhibitors. The marama bean inhibitor is specific for elastase, with very low K(i) for both pancreatic and neutrophil elastase. The quantity of elastase inhibitor present in marama beans is many times greater than in soybean or any other bean or nut source reported to date. This raises the question of why a bean found in an arid corner of the Kalahari Desert would be so rich in a very potent elastase inhibitor.
authors.affiliation: The University of Texas Health Science Center at Tyler, Tyler, TX 75708, USA.
authors.forename: Deepa
authors.initials: D
authors.lastname: Nadaraja
authors.forename: Susan T
authors.initials: ST
authors.lastname: Weintraub
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Hakala
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Sherman
authors.forename: Barry
authors.initials: B
authors.lastname: Starcher
mesh_terms: D000595:Amino Acid Sequence; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D007887:Fabaceae / Q000737:chemistry*; D006031:Glycosylation; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D010940:Plant Proteins; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; D010940:Plant Proteins; D010196:Pancreatic Elastase