Beck E, Wieczorek J, Reinecke W. Purification and properties of hamamelosekinase.
EUROPEAN JOURNAL OF BIOCHEMISTRY 1980;
107:485-9. [PMID:
6249593 DOI:
10.1111/j.1432-1033.1980.tb06054.x]
[Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hamamelosekinase (ATP:hamamelose 2(1)-phosphotransferase) was purified from a crude extract of Kluyvera citrophila 627 (Enterobacteriaeceae) which has been grown on D-hamamelose. Ammonium-sulfate fractionation and twofold chromatography on DEAE-cellulose resulted in a 51-fold purification of the enzyme. Neither glucosekinase nor significant ATPase activity could be detected in the pure preparation. Besides D-hamamelose only D-hamamelitol was utilized as a substrate; however, the latter was phosphorylated at a very low rate. The molecular weight of the enzyme as estimated by gel chromatography is 21 000. The Km values for hamamelose and ATP were 3 mM nd 2.5 mM, respectively. The pH optimum was found at 7.5. In contrast to hexokinase, purified hamamelosekinase is very labile and could only be stabilized by addition of its substrate D-hamamelose. The most unusual property with respect to yeast hexokinase is a pronounced substrate inhibiton by hamamelose (> 5mM) and ATP (> 7mM), respectively, which could be interpreted as due to an economic utilization of the nutrient. Hamamelosekinase as well as glucosekinase are inducible by growing the microorganisms on the corresponding monosaccharides.
Collapse