This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (45) Citing Articles via Google Scholar Google Scholar Articles by Turner, J. F. Articles by Copeland, L. Search for Related Content PubMed PubMed Citation Articles by Turner, J. F. Articles by Copeland, L. Agricola Articles by Turner, J. F. Articles by Copeland, L.

Articles

Fructokinase (Fraction IV) of Pea Seeds ¹

^a Department of Agricultural Chemistry, University of Sydney, N.S.W. 2006, Australia

A fructokinase (EC 2.7.1.4) was obtained from pea (Pisum sativum L.) seeds. This enzyme, termed fructokinase (fraction IV), was specific for fructose as substrate and had little activity with glucose or mannose. Excess fructose inhibited the enzyme at the optimum pH (8.2) but not at pH 6.6. MgATP was inhibitory at pH 6.6. The apparent Michaelis-Menten constants at pH 8.2 were 0.057 mM for fructose and 0.10 mM for MgATP. Mg²⁺ ions were essential for activity; Mn²⁺ could partially replace Mg²⁺. Fructokinase (fraction IV) had a requirement for K⁺ ions which could be substantially replaced by Rb⁺ or NH₄⁺ but not by Na⁺. The enzyme was inhibited by MgADP. The possible significance of fructokinase (fraction IV) in plant carbohydrate metabolism is discussed.