The effects of salicylic acid (SA) and cold on photosynthesis, activities of carboxylating enzymes ribulose-1,5bisphosphate carboxylase (RuBPC) and phosphoenolpyruvate carboxylase (PEPC) and activities of photorespiratory enzymes glycolate oxidase (GO) and catalase (CAT), and on the activies of antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR...

Phosphoenolpyruvate carboxylase isolated from maize (Zea mays L.) leaves was assayed with varying concentrations of free phosphoenolpyruvate at several fixed-varying concentrations of free magnesium higher than required to saturate the enzyme reaction. These assays produced velocity data which were found to form a family of individual lines when plotted against free phosphoenolpyruvate or again...

A specific antibody against liver cytosol phosphoenolpyruvate carboxylase (EC 4.1.1.32) was used to isolate the enzyme from liver and adipose tissue. With this technique we have shown that phosphoenolpyruvate carboxylase synthesis in starved rats accounts for 3% of the total synthesis ofcytosol protein in each tissue. Re-feeding starved animals decreases this relative rate of phosphoenolpyruvat...

Regenerating maize A188 tissue cultures were examined for the presence of enzymes involved in C4 photosynthesis, for cell morphology, and for '4C labeling kinetics to study the implementation of this pathway during plant development. For comparison, sections of maize seedling leaves were examined. Protein blot analysis using antibodies to leaf enzymes showed a different profile of these enzymes...

The effects of adenine nucleotides on phosphoenolypyruvate carboxylase were investigated using purified enzyme from the CAM plant, Crassula argentea. At 1 millimolar total concentration and with limiting phosphoenolpyruvate, AMP had a stimulatory effect, lowering the K(m) for phosphoenolpyruvate, ADP caused less stimulation, and ATP decreased the activity by increasing the K(m) for phosphoenolp...

Phosphoenolpyruvate and oxaloacetate are key intermediates at the junction between catabolism and biosynthesis. Alteration of carbon flow at these branch points will affect the growth yield and the formation of products. We attempted to modulate the metabolic flow between phosphoenolpyruvate and oxaloacetate by overexpressing phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase...