Structural Characterization of Transglutaminase-Catalyzed Casein Cross- LinkingSergio Lilla1,2, Gianfranco Mamone2, Maria Adalgisa Nicolai1, Lina Chianese1, Gianluca Picariello2, Simonetta Caira2 and Francesco Addeo1,2*
- *Corresponding Author:
- Francesco Addeo
Dipartimento di Scienza degli Alimenti
University of Naples “Federico II”
Parco Gussone, Portici 80055, Italy
E-mail: [email protected]
Received date: March 14, 2012; Accepted date: April 06, 2012; Published date: April 08, 2012
Citation: Lilla S, Mamone G, Nicolai MA, Chianese L, Picariello G, et al. (2012) Structural Characterization of Transglutaminase-Catalyzed Casein Cross-Linking. J Chromatograph Separat Techniq 3:122. doi:10.4172/2157-7064.1000122
Copyright: © 2012 Lilla S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Microbial transglutaminase is used in the food industry to improve texture by catalyzing protein cross-linking. Casein is a well-known transglutaminase substrate, but the complete role of glutamine (Q) and lysine (K) residues in its cross-linking is not fully understood. In this study, we describe the characterization of microbial Transglutaminase -modified casein using a combination of immunological and proteomic techniques. Using 5-(biotinamido)pentylamine as an acyl acceptor probe, three Q residues of β-casein and one of αs1-casein were found to participate as acyl donors. However, no Q-residues were involved in network formation with κ-casein or αs2-casein. Q and K residues in the ε-(γ-glutamyl)lysine-isopeptide bonds β-casein were identified by nanoelectrospray tandem mass spectrometry of the proteolytic digests. This work reports our progress toward a better understanding of the function and mechanism of action of microbial transglutaminase-mediated proteins. The results suggest a possible role for transglutaminase in the formation of casein micelles.