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Transglutaminase‐mediated modification of glutamine and lysine residues in native bovine β‐lactoglobulin
Author(s) -
Nieuwenhuizen Willem F.,
Dekker Henk L.,
Gröneveld Toos,
de Koster Chris G.,
de Jong Govardus A. H.
Publication year - 2003
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10898
Subject(s) - deamidation , tissue transglutaminase , lysine , chemistry , glutamine , biochemistry , chemical modification , whey protein , glycine , enzyme , beta lactoglobulin , posttranslational modification , amino acid
Bovine β‐lactoglobulin (BLG) is a major component in whey and its physical properties are important for the texture of many dairy‐based foods. Modification of proteins with transglutaminase from Streptoverticillium mobaraense (MTGase) can be used to alter their physical properties. MTGase‐mediated modification of native BLG was until now, however, not effective. Here we report a method that allows for the enzymatic modification of native BLG with MTGase. Lysines 8, 77, and 141 were modified with α‐ N ‐carbobenzyloxy‐glutamine‐glycine and glutamines 35, 59, 68,and 155 were modified with 6‐aminohexanoic acid under nonreducing and nondenaturing conditions. MTGase‐mediated BLG crosslinking is hampered by the low reactivity of the lysines and enzymatic deamidation of the glutamines prevails. Modification of BLG with poly‐lysine yields a BLG derivative with increased affinity for the water–air interface and stronger surface tension lowering capacities than normal BLG. Hence, this modification method offers the opportunity to change the functional properties of BLG and to prepare novel protein foods. © 2004 Wiley Periodicals, Inc.