Characterization of D-tagatose-3-epimerase from Rhodobacter sphaeroides that converts D-fructose into D-psicose.
A non-characterized gene, previously proposed as the D-tagatose-3-epimerase gene from Rhodobacter sphaeroides, was cloned and expressed in Escherichia coli. Its molecular mass was estimated to be 64 kDa with two identical subunits. The enzyme specificity was highest with D-fructose and decreased for other substrates in the order: D-tagatose, D-psicose, D-ribulose, D-xylulose and D-sorbose. Its activity was maximal at pH 9 and 40 degrees C while being enhanced by Mn(2+). At pH 9 and 40 degrees C, 118 g D-psicose l(-1) was produced from 700 g D-fructose l(-1) after 3 h.
Zhang
Longtao
L
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China. zlongtao@hotmail.com
Mu
Wanmeng
W
Jiang
Bo
B
Zhang
Tao
T
D000595:Amino Acid Sequence; D002238:Carbohydrate Epimerases / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D020536:Enzyme Activators / Q000494:pharmacology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005632:Fructose / Q000378:metabolism*; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012242:Rhodobacter sphaeroides / Q000201:enzymology* / Q000235:genetics; D016415:Sequence Alignment; D013379:Substrate Specificity; D013696:Temperature
D020536:Enzyme Activators; C003243:psicose; D005632:Fructose; D008345:Manganese; D002238:Carbohydrate Epimerases