Protein phosphorylation in pea [Pisum sativum] root plastids

Protein phosphorylation has been investigated in nonphotosynthetic plastids of pea roots. Intact and lysed preparations of plastids were incubated with [gamma-32P]ATP and three stromal proteins of sizes 41, 58 and 62 kDa were phosphorylated on a serine residue. No other proteins were significantly l...

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Bibliographic Details
Published in:	Plant and cell physiology Vol. 42; no. 6; pp. 642 - 649
Main Authors:	Lukaszewski, K.M. (University of Manchester (UK)), Bowsher, C.G, Savory, P.J, Emes, M.J
Format:	Journal Article
Language:	English
Published:	Japan Oxford University Press 01-06-2001 Oxford Publishing Limited (England)
Subjects:	3 phosphoglyeric acid Adenosine Triphosphate - metabolism BIOCHEMICAL PATHWAYS DHAP dihydroxyacetone phosphate Glc1P Glc6P glucose 1-phosphate glucose 6-phosphate Glucose-6-Phosphate - metabolism Hydrogen-Ion Concentration Key words: Pisum sativum — Plastids — Protein phosphorylation — Roots Magnesium - metabolism methyl viologen Nitrites - metabolism OPPP oxidative pentose phosphate pathway PEP PGA PGM phosphoenolpyruvic acid phosphoglucomutase Phosphoproteins - metabolism PHOSPHORYLATION PISUM SATIVUM Pisum sativum - metabolism Plant Proteins - metabolism Plant Roots - metabolism PLASTIDS Plastids - metabolism PROTEINS ROOTS
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Summary:	Protein phosphorylation has been investigated in nonphotosynthetic plastids of pea roots. Intact and lysed preparations of plastids were incubated with [gamma-32P]ATP and three stromal proteins of sizes 41, 58 and 62 kDa were phosphorylated on a serine residue. No other proteins were significantly labelled under the conditions used. The 62 kDa protein is probably phosphoglucomutase and represents a phosphoenzyme catalytic intermediate. The protein kinase(s) and phosphatase(s) acting on the other proteins were not sensitive to exogenous calcium but were sensitive to magnesium. The protein phosphatase which acts on the 41 kDa protein is possibly of type 2C, whereas that acting on the 58 kDa phosphoprotein did not fall into any class defined by mammalian systems. Metabolism of exogenous glucose 6-phosphate by the oxidative pentose phosphate pathway in intact plastids abolished the phosphorylation of the 58 kDa protein. Dihydroxyacetone phosphate, phosphoenolpyruvate and 3-phosphoglycerate also inhibited phosphorylation of the 58 kDa protein and bad a time-dependent effect on the phosphorylation of the 41 kDa protein. The significance of these results in relation to a possible role for protein phosphorylation in these plastids is considered.
Bibliography:	F60 2002001082 istex:2B554D875FD0E248A082EE0B9ABBE3838E322B37 local:pce087 ark:/67375/HXZ-CG9NFR6F-K (Received January 15, 2001; Accepted March 30, 2001). ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0032-0781 1471-9053
DOI:	10.1093/pcp/pce087