Photosynthetic Phosphoenolpyruvate Carboxylases

摘要: A detailed comparison of green leaf phosphoenolpyruvate carboxylases from the C4-species Atriplex spongiosa and C3-species hastata revealed significant physical kinetic differences. The two alloenzymes can be separated by anion exchange chromatography but have comparable molecular weights (350,000). Maximal velocity estimates were 38.0 1.48 micromoles per minute milligram chlorophyll for A. hastata, respectively. Km 0.49 0.08 mm C4A. C3A. Mg 0.33 C4 species 0.017 C3 species. activity carboxylase is more sensitive to chloride phosphate than both are equally chelating substances such as ATP, ADP, citrate if assayed at their respective values. survey 18 resulted in mean maximal 29.0 ± 13.2 1.50 0.57 species, 0.59 0.35 0.14 0.07 C3, 0.50 0.30 0.097 0.057 C3. All differences between means 0.01 confidence level, supporting our hypothesis that plants functionally different associated with photosynthetic roles. Both function production acids, largely producing malate or aspartate (or both) a intermediate product.