title: Calcium ions make phytohemagglutinin resistant to trypsin proteolysis.
abstract: To investigate the mechanism of phytohemagglutinin (PHA) susceptibility or resistance to the action of proteolytic enzymes, its in vitro proteolysis by trypsin was studied. It was found that Ca (2+) gives resistance to the native PHA molecule to trypsin proteolysis. In the absence of Ca (2+) trypsin performs a thorough hydrolysis of PHA. At the first stage of trypsin hydrolysis of PHA the formation of a relatively stable high molecular mass product occurs (PHA-T) as a result of non-co-operative proteolysis. At the second stage, the degradation of PHA-T occurs, and this degradation is performed by parallel co-operative proteolysis. This type of proteolysis differs from the action of trypsin on phaseolin, the main storage protein from common bean ( Phaseolus vulgaris L.). The implications of Ca (2+)influence of PHA hydrolysis by trypsin are discussed.
authors.affiliation: Laboratory of Plant Biochemistry, State University of Moldova, Mateevici str. 60, MD-2009 Kishinev, Republic of Moldova.
authors.forename: Diana
authors.initials: D
authors.lastname: Morari
authors.forename: Tatiana
authors.initials: T
authors.lastname: Stepurina
authors.forename: Vitalie I
authors.initials: VI
authors.lastname: Rotari
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D002413:Cations, Divalent; D004492:Edetic Acid / Q000494:pharmacology; D006868:Hydrolysis; D010835:Phytohemagglutinins / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D010835:Phytohemagglutinins; D010940:Plant Proteins; C048826:phaseolin protein, Phaseolus vulgaris; D004492:Edetic Acid; D014357:Trypsin; D002122:Calcium Chloride; D002118:Calcium