Van Praag E, Gonzalez P, Brune A, Goren R, Zehavi U, Echeverria E
Kennedy-Leigh Centre for Horticultural Research, Hebrew University of Jerusalem, Rehovot, Israel.
Biochem Mol Biol Int. 1998 Jan;44(1):117-25. doi: 10.1080/15216549800201122.
Grapefruit leaf PFP was studied for its activation by fructose 2,6-bisphosphate (Fru 2,6-P2) in the forward and reverse reactions. In the glycolytic reaction, a Ka of 4.0 +/- 0.12 nM was obtained. This constant is affected by the presence of increasing concentrations of citrate (1, 5 and 20 nM) with a Ka(citrate) of 4.5 +/- 0.09, 6.9 +/- 0.05 and 38.2 +/- 1.4 respectively. The inhibition mode of citrate is competitive with Fru 2,6-P2, but non-linear in relation of increasing concentrations of the inhibitor. The intracellular distribution and concentration of the key regulatory metabolite Fru 2,6-P2 was further investigated in citrus leaves and juice cells. Fru 2,6-P2 was only found in the cytosol of juice cells. Fru 2,6-P2 was detected under both conditions with higher concentrations found under aerobiosis.
研究了葡萄柚叶磷酸果糖磷酸酶（PFP）在正向和反向反应中被果糖2,6-二磷酸（Fru 2,6-P2）激活的情况。在糖酵解反应中，获得的解离常数（Ka）为4.0±0.12 nM。该常数受柠檬酸盐浓度增加（1、5和20 nM）的影响，柠檬酸盐的Ka分别为4.5±0.09、6.9±0.05和38.2±1.4。柠檬酸盐的抑制模式与Fru 2,6-P2竞争，但与抑制剂浓度增加呈非线性关系。进一步研究了关键调节代谢物Fru 2,6-P2在柑橘叶片和汁胞中的细胞内分布及浓度。Fru 2,6-P2仅在汁胞的细胞质中被发现。在两种条件下均检测到Fru 2,6-P2，在需氧条件下浓度更高。
