Study On Enzymatic Polymerization Of Food Proteins And Mechanism Of Its Modification

The catalytic characteristics of microbial transglutaminase (MTGase) towards food protein substrates and mechanism of its modification were studied systematacially. Main results are as follows:1. The polymerization of mono-substrate food proteins such as sodium caseinate, bovine serum albumin (BSA), glycinin and β -conglycinin, β -lactoglobulin( β-LG) and α -lactoalbumin ( α-LA) by MTGase were studied by SDS-PAGE combined with the technique of imaging. It showed that sodium caseinate and BSA were the best substrate of MTGase, and glycinin followed, and β-conglycinin and whey proteins were poor substrates of MTGase. According to the differences of catalytic velocity of MTGase towards different proteins, it was considered that those proteins with low surface hydrophobity (So) can be polymerized by MTGase easier, and pre-treatment can improve the catalytic activity of MTGase towards proteins (especially for globular proteins).2. "Induction phase" during the polymerization of globular proteins by MTGase was proved through UV- and FT-IR spectrum. The mechanism of polymerization of globular proteins catalyzed by MTGase was first illustrated.3. The Polymerization of Multi-substrate systems such as β-LG /CN, BSA/β-LG, BSA/CN, glycinin/β-LG,, glycinin/CN and glycinin/BSA by MTGase were studied. It indicated that those different proteins with similar surface hydrophobity (So) could by cross-linked by MTGase to form the hetero-polymers. The model and mechanism of...