Purification and characterization of rat liver transglutaminase.
1. Transglutaminase (EC 2.3.2.13) was purified from rat liver. 2. The enzyme was stable at 25 degrees C in the pH range of 6.0-9.0, with the optimum at pH 9.0. 3. The enzyme was inactivated after incubation for 20, 4 and 1 min at 44 degrees C, 52 degrees C, and 60 degrees C, respectively. 4. Activation energies were 30.4 kcal/mol for denaturation and 19.9 kcal/mol for substrate conversion to products. 5. The enzyme was inactivated by sulfhydryl modification with hydroxymercuribenzoate (99.1%) and N-ethylmalemide (78.5%). 6. Calcium, required for the activity, was replaced to a lesser extent, by Mg2+, Sr2+, Zn2+ and Mn2+ (31.8, 27.0, 24.6 and 3.5%). 7. Steady-state kinetics showed: Vmax = 10 microM-min-1, Km = 0.05 mM (N-dimethylated casein), kcat = 31.9 min-1 kcat/Km = 560 min-1 mM-1.
Wong
W S
WS
Institute of Food Science, Cornell University, Ithaca, NY 14853.
Batt
C
C
Kinsella
J E
JE
D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D006168:Guinea Pigs; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D051381:Rats; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D011503:Transglutaminases / Q000032:analysis*
D013438:Sulfhydryl Compounds; D011503:Transglutaminases