Purification and characterization of mannose isomerase from Agrobacterium radiobacter M-1.
A mannose isomerase from Agrobacterium radiobacter M-1 (formerly Pseudomonas sp. MI) was purified to electrophoretic homogeneity and characterized. A cell-free extract was separated by ammonium sulfate fractionation, Butyl-Toyopearl 650M, DEAE-Sepharose and hydroxylapatite column chromatography. Its molecular mass was estimated to be 44 kDa by SDS-PAGE and 90 kDa by gel filtration, in which the enzyme is most likely a dimer composed of two identical subunits. The purified enzyme had an optimum pH at 8.0, an optimum temperature at 60 degrees C, a pI of 5.2 and a Km of 20 mM, and specifically converted D-mannose and D-lyxose to ketose. The N-terminal amino acid sequence was identified.
Hirose
J
J
Department of Applied Chemistry, Faculty of Engineering, Miyazaki University, Japan. jhirose@cc.miyazaki-u.ac.jp
Maeda
K
K
Yokoi
H
H
Takasaki
Y
Y
D019747:Aldose-Ketose Isomerases / Q000032:analysis* / Q000037:antagonists & inhibitors; D002413:Cations, Divalent; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008670:Metals; D008970:Molecular Weight; D012231:Rhizobium / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
D002413:Cations, Divalent; D004791:Enzyme Inhibitors; D008670:Metals; D019747:Aldose-Ketose Isomerases; C032728:mannose isomerase