Phosphoproteins and protein kinase activities intrinsic to inner membranes of potato tuber mitochondria

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Inside-out submitochondrial particles (IO-SMP) were isolated and purified from potato (Solanum tuberosum L. cv.) tubers. When these IO-SMP were incubated with [γ32P]ATP more then 20 proteins became labelled as a result of phosphorylation. The 32P incorporation was stimulated by the oxidizing reagent ferricyanide. Except for a 17 kDa protein which was phosphorylated only in the absence of divalent cations, the protein phosphorylation required Mg2+. The time for half-maximum 32P incorporation was 4 min for the 22 kDa phospho-F1 δ-subunit and 2 min for the 28 kDa phospho-F0 b-subunit of the proton-ATPase. The K(m) for ATP for the detected phosphoproteins was between 65 μM and 110 μM. The pH optimum for protein phosphorylation in inner membranes was between pH 6 and 8, and for the F1 δ-subunit and the F0 b-subunit the pH optima were 6.5-8 and pH 8, respectively. A 37 kDa phosphoprotein was phosphorylated on a histidine residue while the remainder of the inner membrane proteins were phosphorylated on serine or threonine residues. Two autophosphorylated putative kinases were identified: one at 16.5 kDa required divalent cations for autophosphorylation, while another at 30 kDa did not. A 110 kDa protein was labelled only with [α-32P]ATP, suggesting adenylylation.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • Lund University
  • Novartis Seeds AB
Forskningsområden

Nyckelord

Originalspråkengelska
Sidor (från-till)1271-1279
Antal sidor9
TidskriftPlant and Cell Physiology
Volym40
Utgåva nummer12
StatusPublished - 1999
PublikationskategoriForskning
Peer review utfördJa