Open AccessThe amine‐donor substrate specificity of tissue‐type transglutaminase
Author(s) -
GROENEN Patricia J. T. A.,
SMULDERS Ronald H. P. H.,
PETERS Roderick F. R.,
GROOTJANS Johan J.,
IJSSEL Paul R. L. A.,
BLOEMENDAL Hans,
JONG Wilfried W.
Publication year - 1994
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1994.tb18681.x
Subject(s) - tissue transglutaminase , lysine , chemistry , residue (chemistry) , arginine , alanine , amine gas treating , biochemistry , amino acid , glutamine , substrate (aquarium) , stereochemistry , enzyme , biology , organic chemistry , ecology
The amine‐donor substrate specificity of tissue‐type transglutaminase has been studied in a series of recombinant αA‐crystallin mutants. These mutant proteins have been provided with a potential substrate lysine residue, flanked by different amino acid residues, in the C‐terminal extended arm of αA‐crystallin. A biotinylated amine‐acceptor hexapeptide was used as a probe for labelling the amine‐donor sites. Wild‐type bovine αA‐crystallin does not function as an amine‐donor substrate for tissue‐type transglutaminase. Yet, upon introduction of a lysine residue at the C‐terminal or penultimate position, all mutant αA‐crystallins act as amine‐donor substrates, although to different extents. This shows that accessibility is the primary requirement for a lysine residue to function as an amine‐donor substrate for transglutaminase and that the enzyme has a broad tolerance towards the neighbouring residues. However, the nature of the flanking amino acid residues does clearly affect the reactivity of the substrate lysine residue. Notably, we found that a proline or glycine residue in front of the substrate lysine has a strong adverse effect on the substrate reactivity as compared to a preceding leucine, serine, alanine or arginine residue.