Isolation and characterization of a proteinase inhibitor from marama beans.
A protease inhibitor was purified from the African marama bean (Tylosema esculenturm). The inhibitor is present in large amounts, representing about 10.5% of the total protein. The molecular weight is slightly larger than soybean trypsin inhibitor and was estimated at 23,000 by SDS-gel electrophoresis or 24,500 by amino acid analysis. The amino acid composition was atypical of most other plant inhibitors with a cysteine content of only one or possibly two residues/mole and a blocked amino terminus. Inhibition studies indicated virtually no inhibition of chymotrypsin activity. Elastase, however, was inhibited to the same extent as trypsin, requiring about 2 moles of inhibitor for complete inhibition of the enzyme.
D000596:Amino Acids / Q000032:analysis; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D007887:Fabaceae / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D010940:Plant Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D010945:Plants, Edible / Q000201:enzymology*; D010946:Plants, Medicinal; D013379:Substrate Specificity; D014361:Trypsin Inhibitors / Q000302:isolation & purification
D000596:Amino Acids; D010940:Plant Proteins; D014361:Trypsin Inhibitors; C046908:protease inhibitor protein, Tylosema esculenturm; D002918:Chymotrypsin; D010196:Pancreatic Elastase