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Title: EXPLORING THE CROSS-LINKING REACTION MECHANISM OF GENIPIN WITH BETA-LACTOGLOBULIN AND RELATED PEPTIDES BY MALDI-TOF/TOF MASS SPECTOMETRY

Author
item Qi, Phoebe
item Nunez, Alberto
item Tomasula, Peggy

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/9/2008
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: Genipin, a traditional herbal medicine obtained from the fruit of Gardenia jasminoides, has recently attracted much attention because it is 10,000 times less cytotoxic than traditional crosslinking agents such as glutaraldehyde. Genipin has been shown to be capable of cross-linking the primary amine groups of proteins such as the epsilon-amino groups of lysine, and to a lesser extent, of arginine and glutamine. However, the mechanism of the cross-linking reaction is not fully understood. In this study, we examined the reactions of the tryptic peptides of b-lactoglobulin and other synthetic peptides with genipin using MALI-TOF/TOF mass spectrometry. The results from kinetics studies clearly identified reaction intermediates during the cross-linking reactions and the final products formed subsequently. The reaction intermediates, resulting from nucleophilic attack by the amine at two sites of the genipin molecule, proceeded to successfully cross-link. In addition, a by-product derived from a simple addition of a monomeric genipin molecule to the N-terminus of a peptide, not reported previously, was observed and may cause the termination of the cross-linking reaction as a competitive reaction scheme. The significance of this work lies in establishing appropriate reaction conditions that can be adapted effectively in cross-linking agricultural proteins such as whey proteins using genipin to produce novel food and non-food products.