Differential temperature sensitivity of pea superoxide dismutases.
The activity of pea (Pisum sativum L.) Cu/Zn and Mn superoxide dismutase isoforms was evaluated across a range of temperatures from 10 to 45 degrees C. Maximal activity of the Cu/Zn and Mn superoxide dismutase isoforms was observed at 10 degrees C. Both cytoplasmic and chloroplast Cu/Zn superoxide dismutases exhibit a reduction in staining intensity with increasing temperatures. Mn superoxide dismutase, however, maintained a relatively constant staining intensity across the range of temperatures evaluated. An unrelated enzyme used as a control, malate dehydrogenase, exhibited the expected increase in staining activity with increasing temperatures. These results describe a unique response of a protection enzyme to temperature.
Burke
J J
JJ
U.S. Department of Agriculture-Agricultural Research Service Cropping Systems Research Laboratory, Route 3, Box 215, Lubbock, Texas 79401.
Oliver
M J
MJ