Ability of Kocuria varians LTH 1540 To Degrade Putrescine: Identification and Characterization of a Novel Amine Oxidase

This work describes the identification and characterization of an amine oxidase from Kocuria varians LTH 1540 (syn. Micrococcus varians) primarily acting on putrescine. Data from MALDI-TOF MS/MS and the identification of Delta(1)-pyrroline as degradation product from putrescine indicates that the enzyme is a flavin-dependent putrescine oxidase (PuO). Properties of partially purified enzyme have been determined. The enzyme oxidizes diamines, putrescine and cadaverine and, to a lesser extent, polyamines such as spermidine but not monoamines. The kinetic constants (K-m and V-max) for the two major substrates were 94 +/- 10 mu M and 2.3 +/- 0.1 mu mol/min.mg for putrescine and 75 +/- 5 muM and 0.15 +/- 0.02 mu mol/min.mg for cadaverine. Optimal temperature and pH were 45 degrees C and 8.5, respectively Enzyme was stable until 50 degrees C. K. varians PuO is sensitive to human flavin-dependent amine oxidase inhibitors, and carboxyl modifying compounds. The new enzyme has been isolated from a bacterial starter used in the manufacture of fermented meat. One of the problems of fermented foods or beverages is the presence of toxic biogenic amines produced by bacteria. The importance of this works lies in the description of a new enzyme able to degrade two of the most abundant biogenic amines (putrescine and cadaverine), whose use could be envisaged to diminish biogenic amines content in foods in the future.