Fructose metabolism in plants. Isolation and properties of pea seed frucktokinase
Frankart, W.A.; Pontis, H.G.
Acta Physiologica Latino Americana 26(5): 319-329
1976
ISSN/ISBN: 0001-6764 PMID: 210626 Document Number: 102981
Fructokinase from pea (Pisum sativum L.) seed was purified 100-fold. The enzyme required reduced sulfhydryl groups for activity. It also exhibits an absolute requirement for K+ (Km = 3 mM) and it unstable when not stored with a high concentration of K+. The isoelectric point of the enzyme is 4.7 and it has a MW of 44,000 .+-. 700 daltons as determined by molecular sieve chromatography and sedimentation velocity techniques. A Hill plot of the K+ data suggests that 2 K sites are present on the enzyme. The MgATP saturation curve was non-Michaelis-Menten with a slight positive cooperativity. Pea seed fructokinase is highly specific for fructose and ATP. A comparison of pea seed fructokinase properties and those of liver origin is presented.