
TY  - JOUR
A1  - Diakou, Paraskevi 
A1  - Svanella, Laurence 
A1  - Raymond, Philippe 
A1  - Gaudillère, Jean-Pierre 
A1  - Moing, Annick 
T1  - Phospho<emph type="2">enol</emph>pyruvate carboxylase during grape berry development: protein level, enzyme activity and regulation
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2000
VL  - 27
IS  - 3
SP  - 221
EP  - 229
KW  - Vitis vinifera, metabolism, regulation, 14 C labelling, organic acids, malate.
UR  - https://doi.org/10.1071/PP99141 
N2  - The protein level and regulation of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31, involved in malic acid synthesis) was studied during the fruit development of two grape (Vitis vinifera L.) varieties, &#8216;Cabernet Sauvignon&#8217; and &#8216;Gora Chirine&#8217;, with berries of normal and low organic acid content, respectively. The protein level and in vitro activity were higher in the low-acid variety than in the normal-acid variety for most stages. In vivo PEPC activity, measured using 14 CO2 labelling, was significantly higher in the low-acid variety than in the normal-acid variety about 1 week before and 1 week after veraison (the day which corresponds to the onset of ripening). However, partitioning into malate was the same for both varieties. Antibodies raised against the N-terminal part of SorghumPEPC recognised the grape berry PEPC, indicating the presence of the consensus phosphorylation site involved in PEPC regulation. PEPC phosphorylation status was estimated by studying sensitivity to pH and malate. Grape berry PEPC appeared more sensitive to low pH and malate during ripening (IC50 malate, 0.2&#8211;0.7 mM) compared to during the earlier stages of development (IC50 malate, 1.2&#8211;2 mM) for both varieties. Therefore, in the normal-acid variety, PEPC seems to participate in controlling malic acid accumulation but does not seem to control the differences in malic acid concentration observed between the two varieties. 
ER  -

