Alkaline phytase from lily pollen: Investigation of biochemical properties
Document Type
Article
Publication Date
8-15-2005
Department
Department of Chemistry
Abstract
Phytases catalyze the hydrolysis of phytic acid (InsP6, myo-inositol hexakisphosphate), the most abundant inositol phosphate in cells. In cereal grains and legumes, it constitutes 3-5% of the dry weight of seeds. The inability of humans and monogastric animals such as swine and poultry to absorb complexed InsP6 has led to nutritional and environmental problems. The efficacy of supplemental phytases to address these issues is well established; thus, there is a need for phytases with a range of biochemical and biophysical properties for numerous applications. An alkaline phytase that shows unique catalytic properties was isolated from plant tissues. In this paper, we report on the biochemical properties of an alkaline phytase from pollen grains of Lilium longiflorum. The enzyme exhibits narrow substrate specificity, it hydrolyzed InsP6 and para-nitrophenyl phosphate (pNPP). Alkaline phytase followed Michaelis-Menten kinetics with a Km of 81 μM and Vmax of 217 nmol Pi/min/mg with InsP6 and a Km of 372 μM and Vmax of 1272 nmol Pi/min/mg with pNPP. The pH optimum was 8.0 with InsP6 as the substrate and 7.0 with pNPP. Alkaline phytase was activated by calcium and inactivated by ethylenediaminetetraacetic acid; however, the enzyme retained a low level of activity even in Ca2+-free medium. Fluoride as well as myo-inositol hexasulfate did not have any inhibitory affect, whereas vanadate inhibited the enzyme. The enzyme was activated by sodium chloride and potassium chloride and inactivated by magnesium chloride; the activation by salts followed the Hofmeister series. The temperature optimum for hydrolysis is 55°C; the enzyme was stable at 55°C for about 30 min. The enzyme has unique properties that suggest the potential to be useful as a feed supplement.
Publication Title
Archives of Biochemistry and Biophysics
Recommended Citation
Jog, S.,
Garchow, B.,
Mehta, B.,
&
Murthy, P.
(2005).
Alkaline phytase from lily pollen: Investigation of biochemical properties.
Archives of Biochemistry and Biophysics,
440(2), 133-140.
http://doi.org/10.1016/j.abb.2005.05.029
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/5874