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. 1978 Aug;62(2):291–294. doi: 10.1104/pp.62.2.291

Fructokinase (Fraction III) of Pea Seeds 1

Les Copeland 1, Dorothy D Harrison 1, John F Turner 1
PMCID: PMC1092108  PMID: 16660504

Abstract

A second fructokinase (EC 2.7.1.4) was obtained from pea seed (Pisum sativum L. var. Progress No. 9) extracts. The enzyme, termed fructokinase (fraction III), was specific for fructose and had little activity with glucose. With fructose concentrations above 0.25 millimolar, there was strong substrate inhibition at the optimum pH (8.0) and also at pH 6.6. The apparent Km values at pH 8.0 for fructose and glucose were 0.06 millimolar and 0.14 millimolar, respectively. The apparent Km for Mg adenosine 5′-triphosphate (MgATP) was 0.06 millimolar and excess MgATP was inhibitory. Mg2+ was essential for activity but the enzyme was inhibited by excess Mg2+ or ATP. Mg adenosine 5′-pyrophosphate was also inhibitory. Activity was stimulated by the addition of monovalent cations: of those tested K+, Rb+, and NH4+ were the most effective. The possible role of fructokinase (fraction III) is discussed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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