EFFECT OF CALCIUM AND ZINC IONS ON THE SENSITIVITY OF PEROXIDASE FROMMOSSES (MNIUM SP) AND FERNS (POLYPODIUM VULGARE) TO HIGH-TEMPERATURE

Incubation of peroxidase from Mnium sp. and Polypodium vulgare with ca lcium or zinc ions caused an activation or inhibition. The enzyme was thermostabilized. The pronounced effect of calcium is interpreted as t he result of its established structural role in the enzyme molecule an d the hypothesis that calcium maintains the peptide bonds around the a ctive site. The individual peroxidase isoenzymes reacted differently t o metal ions added and to increased temperatures. These results are im portant for characterization of metabolic response to environmental st ress and can be used in biological monitoring.