Sucrose Phosphate Synthase (SPS)

Sucrose synthesis is a major element of the interactions between photosynthesis and plant growth and development. increased leaf SPS activity appears to result in increased fruit sugar content since all three lines with increased leaf SPS usually also had increased fruit sugars. Sucrose phosphate synthase was purified from sweet potato callus grown under different conditions, including illumination, darkness, and osmotic stress. The properties of the enzymes purified from the different conditions were compared. Since sucrose synthase could also be purified using the purification process, the expression patterns and properties of the two enzymes were also compared. The SPS purified from the calli tissue medium under illumination had an optimum pH of 7.5. The enzyme had an optimum reaction temperature of 37°C, and maintained stable activity at pH 6 to 8.