Calcium‐ and phospholipid‐dependent phosphorylation of ribulose‐1,5‐bisphosphate carboxylase/oxygenase small subunit by a chloroplast envelope‐bound protein kinase in situ

摘要

>Phosphorylation of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit and other polypeptides by a protein kinase bound to the chloroplast envelope in situ was inhibited by EGTA, but not by calmodulin antagonists. When the envelope membrane was extracted with 90% ( data-equation-construct="true" class="math-equation-construct"> data-equation-image="true" class="math-equation-image"> alt="math formula" src="http://onlinelibrary.wiley.com/store/10.1016/0014-5793(85)80085-5/asset/equation/feb20014579385800855-math-si1.gif?v=1&s=608b47dc812e346dd2c707f28d64805fdc59f25f" class="inlineGraphic" /> data-equation-mathml="true" class="math-equation-mathml" style="display:none">) cold acetone, the protein kinase activity was completely lost. The activity was restored by adding a lipid fraction extracted from the chloroplast envelope, or phospholipids such as phosphatidylserine and phosphatidylcholine. Treatment of the envelope with phospholipases decreased the protein kinase activity. This was restored by the addition of phospholipids. These results strongly suggest that the envelope-bound protein kinase is a Ca2+-and phospholipid-dependent enzyme.