Back to Search
Start Over
Hydrolysis of γ:ϵ Isopeptides by Cytosolic Transglutaminases and by Coagulation Factor XIIIa
- Source :
- Journal of Biological Chemistry. 272:10311-10317
- Publication Year :
- 1997
- Publisher :
- Elsevier BV, 1997.
-
Abstract
- Nepsilon-(gamma-glutamyl)lysine cross-links, connecting various peptide chain segments, are frequently the major products in transglutaminase-catalyzed reactions. We have now investigated the effectiveness of these enzymes for hydrolyzing the gamma:epsilon linkage. Branched compounds were synthesized, in which the backbone on the gamma-side of the cross-bridge was labeled with a fluorophor (5-(dimethylamino)-1-naphthalenesulfonyl or 2-aminobenzoyl) attached through an epsilon-aminocaproyl linker in the N-terminal position, and the other branch of the bridge was constructed with Lys methylamide or diaminopentane blocked by 2,4-dinitrophenyl at the Nalpha position. Hydrolysis of the cross-link could be followed in these internally quenched substrates by an increase in fluorescence. In addition to the thrombin and Ca2+-activated human coagulation Factor XIIIa, cytosolic transglutaminases from human red cells and from guinea pig liver were tested. All three enzymes were found to display good isopeptidase activities, with Km values of 10(-4) to 10(-5) M. Inhibitors of transamidation were effective in blocking the hydrolysis by the enzymes, indicating that expression of isopeptidase activity did not require unusual protein conformations. We suggest that transglutaminases may play a dynamic role in biology not only by promoting the formation but also the breaking of Nepsilon-(gamma-glutamyl)lysine isopeptides.
- Subjects :
- Stereochemistry
Guinea Pigs
Lysine
Glutamic Acid
Peptide
Biochemistry
Structure-Activity Relationship
Hydrolysis
Cytosol
Thrombin
medicine
Animals
Humans
Molecular Biology
chemistry.chemical_classification
Transglutaminases
Cell Biology
Methylamide
Hydrogen-Ion Concentration
Isopeptidase activity
Kinetics
Spectrometry, Fluorescence
Enzyme
chemistry
Calcium
Peptides
Linker
medicine.drug
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 272
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....aa3f0e10fbb3860f94cb234f038d7053