title: Abundant class III acidic chitinase homologue in tamarind (Tamarindus indica) seed serves as the major storage protein.
abstract: The phyla Leguminosae contains protease inhibitors, lectins, chitinases, and glycohydrolases as major defense proteins in their seeds. Electrophoretic analysis of the seed proteins of tamarind ( Tamarindus indica L.), an agri-waste material, indicated the unusual presence of two major proteins comparable to overexpression of recombinant proteins. These proteins were identified by amino-terminal analysis to be (1) Kunitz-type trypsin inhibitor and (2) class III endochitinase (34000 Da). These two proteins were purified to apparent homogeneity by a single-step chitin bead affinity chromatography and characterized. The Kunitz inhibitor was specific toward inhibiting trypsin with a stoichiometry of 1:1. The 33000 +/- 1000 Da protein, accounting for >50% of the total seed protein, is an acidic glycoprotein exhibiting a very low endotype hydrolytic activity toward chitin derivatives. SDS-PAGE followed by densitometry of tamarind seed germination indicates the disappearance of the chitinase with the concomitant appearance of a cysteine endopeptidase. On the basis of its abundance, accumulation without any pathogenesis-related stimulus, temporal regulation, amino acid composition, and very low enzyme activity, this 34000 Da protein designated "tamarinin" physiologically serves as the major storage protein.
authors.affiliation: Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore 570020, India.
authors.forename: Devavratha H
authors.initials: DH
authors.lastname: Rao
authors.forename: Lalitha R
authors.initials: LR
authors.lastname: Gowda
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002688:Chitinases / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000032:analysis*; D012639:Seeds / Q000201:enzymology*; D029861:Tamarindus / Q000201:enzymology*; D013696:Temperature; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D000596:Amino Acids; D010940:Plant Proteins; D014361:Trypsin Inhibitors; D002688:Chitinases; C110892:chitinase, class III