The influence of salts and temperature on enzymatic activity of microbial transglutaminase

Microbial transglutaminase is used world-wide to improve the texture and to modify the properties of prepared foods in general. It was of interest to investigate the influence of different salts (KCl, NaCl, CaCl₂, MgCl₂) and salt concentrations (0%, 5%, 10%, 15%, 20%) on the enzymatic activity and thermal stability of microbial transglutaminase. The food enzyme preparation Activa WM (Ajinomoto Europe Sales. Hamburg) was examined using the hydroxamate test. Compared to the microbial transglutaminase solution in water, the addition of NaCl and KCl (monovalent ions) increased the enzymatic activity and thermal stability. By contrast, bivalent ions either had only a slight influence (MgCl₂) or decreased the enzymatic activity and thermal stability (CaCl₂).