Phosphoproteins and Protein Kinase Activities Intrinsic to Inner Membranes of Potato Tuber Mitochondria |
| |
Authors: | Struglics Andre; Fredlund Kenneth M; Moller Ian M; Allen John F |
| |
Institution: | 1 Plant Cell Biology, Lund University Box 7007, S-220 07 Lund, Sweden
2 Plant Physiology, Lund University Box 117, S-221 00 Lund, Sweden |
| |
Abstract: | Inside-out submitochondrial particles (IO-SMP) were isolatedand purified from potato (Solanum tuberosum L. cv.) tubers.When these IO-SMP were incubated with 32P]ATP more then 20proteins became labelled as a result of phosphorylation. The32P incorporation was stimulated by the oxidising reagent ferricyanide.Except for a 17 kDa protein which was phosphorylated only inthe absence of divalent cations, the protein phosphorylationrequired Mg2+. The time for half-maximum 32P incorporation was4 mm for the 22 kDa phospho-F1 -subunit and 2 min for the 28kDa phospho-F0 b-subunit of the proton-ATPase. The Km for ATPfor the detected phosphoproteins was between 65 µM and110 µM. The pH optimum for protein phosphorylation ininner membranes was between pH 6 and 8, and for the F1 -subunitand the F0 b-subunit the pH optima were 6.58 and pH 8,respectively. A 37 kDa phosphoprotein was phosphorylated ona histidine residue while the remainder of the inner membraneproteins were phosphorylated on serine or threonine residues.Two autophosphorylated putative kinases were identified: oneat 16.5 kDa required divalent cations for autophosphorylation,while another at 30 kDa did not. A 110 kDa protein was labelledonly with -32P] suggesting adenylylation.
3 Present address; Novartis Seeds AB, Box 302, S-261 23 Landskrona,Sweden. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|