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Characterization of hexose kinases from camellia and lily pollen grains
Author(s) -
Nakamura Norio,
Shimizu Minoru,
Suzuki Hiroshi
Publication year - 1991
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1991.tb02132.x
Subject(s) - fructokinase , fructose , invertase , hexokinase , biochemistry , hexose , biology , pollen , camellia , chemistry , enzyme , botany , glycolysis
Extracts from Camellia japonica, Lilium longiflorum and L. lancifolium pollen grains showed a far higher kinase activity with fructose than with glucose. Fructokinase (EC 2.7.1.4) and hexokinase (EC 2.7.1.1) preparations were obtained by partial fractionation of the extracts by DEAE‐cellulose chromatography; the former was practically inactive with glucose. All had a pH optimum at 7.0–8.0 and required Mg 1+ ions for activity with optima at 0.5‐1 m M and 1‐2 m M for fructokinase and hexokinase activities, respectively. Fructokinases had K m of 0.2‐0.4 m M for fructose and similar affinities for ATP and UTP, and were inhibited by fructose above 1 m M . Hexokinases had a higher affinity for glucose than for fructose and a lower affinity for UTP compared to ATP. In camellia pollen most of hexose kinase activities were found to be due to fructokinase. These results are discussed in relation to stimulation of camellia pollen tube growth by oligosaccharides susceptible to invertase (EC 3.2.1.26).