| 摘要 |
4-Chloro-4- deoxy-l-arbinopyranosyl-1,6- dichloro-1,6 dideoxyfructofuranoside (i.e. 4,1',6'-trichloro-4,1',6' trideoxy arabinosucrose) is new. (I, A = CH2OH, Y = Cl). - Prepn. of cpds. (I) (A = H or CH2X; X = H, OH or alkoxy; Y = halo) is effected by reacting an aldose (II) with a fructosyl di- or oligo-saccharide in the presence of fructosyl transferase to give (III). (III) is then chlorinated and opt. deprotected to give (I). A' = H or CH2X'. X' = H, alkoxy or protected OH. - Fructosyl transferase with the following characteristics - a Km to sucrose of at least 0.1M in the absence of an acceptor aldose which does not form significant amounts of alcohol precipitable material from a fructose donor in the absence of an acceptor aldose; and which is unaffected by the presence of surfactants, has an optimum activity at about 30 deg.C. and is active for at least 20 minutes at up to 45 deg.C. EPAB- EP-130054 B 4-Chloro-4- deoxy-l-arbinopyranosyl-1,6- dichloro-1,6 dideoxyfructofuranoside (i.e. 4,1',6'-trichloro-4,1',6' trideoxy arabinosucrose) is new. (I, A = CH2OH, Y = Cl). - Prepn. of cpds. (I) (A = H or CH2X; X = H, OH or alkoxy; Y = halo) is effected by reacting an aldose (II) with a fructosyl di- or oligo-saccharide in the presence of fructosyltransferase to give (III). (III) is then chlorinated and opt. deprotected to give (I). A' = H or CH2X'. X' = H, alkoxy or protected OH. - Fructosyltransferase with the following characteristics - a Km to sucrose of at least 0.1M in the absence of an acceptor aldose which does not form significant amounts of alcohol precipitable material from a fructose donor in the absence of an acceptor aldose; and which is unaffected by the presence of surfactants, has an optimum activity at about 30 deg.C. and is active for at least 20 minutes at up to 45 deg.C. (43pp Dwg.No.0/0) - EP-130054 B An enzyme isolated from bacteria, which enzyme hydrolyses a donor fructosyl oligosaccharide or di-saccharide containing an unsubstituted B-fructosyl ring attached to the anomeric carbon atom of an aldose by a (1-2) linkage and transfer the fructosyl moiety so released to an acceptor aldose to yield a fruxtosyl disaccharide as the main product, the enzyme being capable of forming 6-substituted sucrose derivatives as the main product when the acceptor aldose is a 6-substituted glucose, the enzyme producing no significant amounts of alcohol-precipitatable oligo-or polyfructoses in the presence or absence of an aldose acceptor, the enzyme having a Km for sucrose of at least 0.1 M in the absence of an aldose acceptor and being substantially free from invertase activity. (15pp) - EP-130054 B 4-Chloro-4- deoxy-l-arbinopyranosyl-1,6- dichloro-1,6 dideoxyfructofuranoside (i.e. 4,1',6'-trichloro-4,1',6' trideoxy arabinosucrose) is new. (I, A = CH2OH, Y = Cl). - Prepn. of cpds. (I) (A = H or CH2X; X = H, OH or alkoxy; Y = halo) is effected by reacting an aldose (II) with a fructosyl di- or oligo-saccharide in the presence of fructosyl transferase to give (III). (III) is then chlorinated and opt. deprotected to give (I). A' = H or CH2X'. X' = H, alkoxy or protected OH. - Fructosyl transferase with the following characteristics - a Km to sucrose of at least 0.1M in the absence of an acceptor aldose which does not form significant amounts of alcohol precipitable material from a fructose donor in the absence of an acceptor aldose; and which is unaffected by the presence of surfactants, has an optimum activity at about 30 deg.C. and is active for at least 20 minutes at up to 45 deg.C. (Dwg.0/0) GBAB- GB2145080 B An enzyme isolated from bacteria, which enzyme hydrolyses a donor fructosyl oligosaccharide or disaccharide containing a unsubstituted beta-fructosyl ring attached to the anomeric carbon atom of an aldose by a (1-2) linkage and transfers the fructosyl moiety so released to an acceptor aldose to yield a fructosyl disaccharide as the main product, the enzyme being capable of forming 6-substituted sucrose derivatives as the main product when the acceptor aldose is a 6-substituted glucose, the enzyme producing no significant amounts of alcohol-precipitatable oligo-or polyfructoses in the presence or absence of an aldose acceptor, the enzyme having a Km for sucrose of at least 0.1M in the absence of an aldose acceptor and being substantially free from invertase activity.e USAB- US4617269 A Halodeoxy sucrose of galactosucrose deriv. of formula (I) is prepd. by (a) reacting an aldose of formula (II) with a fructosyl-di- or oligosaccharide using a fructosyltransferase to form cpd. of formula (III); and (b) deprotecting protected -OH gp. - A is H or CH2X; X is H, opt. protected OH, or alkoxy; and Y is halogen. Enzyme is isolated from bacteria and hydrolyses a donor fructosyl oligo- or disaccharide contg. an unsubstd. fructosyl ring attached to the anomeric-C of the aldose by a (1-2) released fructosyl gp. to an aldose-acceptor to form a fructosyl disaccharide as main prod. Enzyme can form 6-substd. sucrose deriv. as main prod. when aldose-acceptor is 6-substd. glucose. |
