Premium
Rat gastrointestinal transglutaminase: Demonstration of enzyme activity and cell and tissue distributions
Author(s) -
Patel Ella K.,
Bruce Sally E.,
Bjarnason Ingvar,
Peters Timothy J.
Publication year - 1985
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.290030307
Subject(s) - tissue transglutaminase , putrescine , crypt , enzyme , cell , biochemistry , chemistry , enzyme assay , cell growth , jejunum , intestinal mucosa , enterocyte , biology , microbiology and biotechnology , medicine , endocrinology , small intestine
The properties, tissue and cellular distribution of intestinal transglutaminase have been investigated. Transglutaminase was assayed with dimethylcasein and [ 14 C]putrescine as substrates. The enzyme has maximum activity at pH 10, although more reliable assays are made at pH 9. Transglutaminase showed an absolute requirement for Ca 2+ and exhibited linear assay kinetics. The K m for putrescine was approx. 0·15 mmol/I. Tissue distribution studies suggest transglutaminase is more active in the more muscular segments of the gut. The cellular localization in jejunum was investigated by sequential cell release techniques. Approximately 2 per cent of the total activity was found in the enterocytes and crypt cells. Most of the activity was in the submucosa and serosa suggesting an interstitial cell localization. Acute hypoplastic enteropathy induced by methotrexate was accompanied by a striking decrease in mucosal transglutaminase but the activity returned to control values by 72 h. There was no significant increase in activity during the period of intense crypt cell hyperplasia and it is concluded that intestinal transglutaminase is not implicated in crypt cell proliferation.