Identification of New Protein Substrate Candidates of Transglutaminase in Rat Liver Extracts: Use of 5-(Biotinamido) Pentylamine as a Probe

摘要

We isolated amine acceptor protein substrates of transglutaninase in rat liver extract using of 5-(biotinamido) pentylamine as a biotin-labeling probe. Three proteins with a molecular mass of 40, 42, and 45 kDa were main components of labeled proteins. Using amino acid sequence analyses and sequence homol-ogy searches, the 40, 42, and 45 kDa proteins were identified as arginase-I (EC 3.5.3.1), fructose-1,6-bisphosphatase (EC 3.1.3.11), and betaine-homocysteine S-methyltransferase (EC 2.1.1.5), respectively. These results were also confirmed by immunoblotting analyses. Arginase-I and fructose-1,6-bisphosphatase are the new protein substrate candidates of transglutaminase, suggesting that these two enzymes can be modified post-translationally by cellular transglutaminase.