Some biochemical properties of swine uterus carnosinase

Carnosinase of swine uterus reacts strongly to Mn2+ ions with an increase of the activity: in the presence of 0.25 MnCl2 the activity increases over 5-fold, while at 1 and 2 mM--the increase is 8- and 10-fold respectively. The enzyme is characterized by low stability during storage, especially in the presence of manganese ions. Kinetic properties of uterus carnosinase change depending on a phase of the oestrous cycle of the sow. In the peak luteal phase (5th-13th day of the cycle) Km values were twice as high as in the follicular phase (zero day--beginning of the rut, and 19th day--preoestrus). Two molecular forms of carnosinase were found in the extracts from uterus in the luteal phase of the oestrous cycle, analysed with the method of Sephadex G-100 gel filtration. These were A and B forms, with predominating content of the latter form. This form was characterised by a 2-fold higher Km value compared to the form A.