title: Effects of Ca2+ and sulfhydryl reductant on the polymerization of soybean glycinin catalyzed by mammalian and microbial transglutaminases.
abstract: Two types of transglutaminases (TGases), Ca(2+)-dependent TGase derived from guinea pig liver (GTGase) and Ca(2+)-independent TGase derived from a variant of Streptoverticillium mobaraense (MTGase), were used to study the cross-linking of soybean 11S globulin (glycinin). The effects of sulfhydryl reductant (dithiothreitol, DTT) and Ca(2+) on the conformation and TGase-catalyzed polymerization of glycinin were investigated. The conformational change of glycinin was probed by spectral methods. The degree of cross-linking and the polymer (aggregate) formation were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and dynamic light scattering, respectively. Addition of DTT stimulated the TGase-catalyzed cross-linking reactions without destroying the secondary and tertiary structure of glycinin but did not influence the polymer or aggregate formation. It was found that Ca(2+) caused the formation of larger size polymers at lower concentrations, while it suppressed the polymerization at higher concentrations. In addition, the cross-linking behaviors of glycinin were shown to be different between MTGase- and GTGase-catalyzed systems.
authors.affiliation: Laboratory of Quality Analysis and Assessment, Division of Agronomy and Horticultural Science, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Japan.
authors.forename: Guoyan
authors.initials: G
authors.lastname: Zhang
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Yukako
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Mori
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002942:Circular Dichroism; D003432:Cross-Linking Reagents; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005916:Globulins / Q000737:chemistry / Q000378:metabolism*; D006168:Guinea Pigs; D008027:Light; D008099:Liver / Q000201:enzymology; D011108:Polymers / Q000378:metabolism*; D011487:Protein Conformation; D012542:Scattering, Radiation; D030262:Soybean Proteins; D013025:Glycine max / Q000737:chemistry*; D013302:Streptomyces / Q000201:enzymology; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D011503:Transglutaminases / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D005916:Globulins; D011108:Polymers; D030262:Soybean Proteins; D013439:Sulfhydryl Reagents; C011474:glycinin; D011503:Transglutaminases; D002118:Calcium; D004229:Dithiothreitol