118291-90-0Relevant articles and documents
Chemoenzymatic preparation of 2-chloro-4-nitrophenyl β-maltooligosaccharide glycosides using glycogen phosphorylase b
Kandra, Lili,Gyemant, Gyoengyi,Liptak, Andras
, p. 180 - 186 (1999)
In the present work, we aimed to develop a new chemoenzymatic procedure for the synthesis of β-maltooligosaccharide glycosides. The primer in the enzymatic reaction was 2-chloro-4-nitrophenyl β-maltoheptaoside (G7-CNP), which was synthesised from β-cyclodextrin (β-CD) using a very convenient chemical method [E. Farkas, L. Janossy, J. Harangi, L. Kandra, A. Liptak, Carbohydr. Res., 303 (1997) 407-415]. Shorter chain length CNP-maltooligosaccharides in the range of dp 3-6 were prepared using rabbit skeletal muscle glycogen phosphorylase b (EC 2.4.1.1). Detailed enzymological investigations revealed that the conversion of G7-CNP was highly dependent on the conditions of phosphorolysis. A 100% conversion of G7-CNP was achieved during 10 min in 1 M phosphate buffer (pH 6.8) at 30°C with the tetramer glycoside (77%) as the main product. Phosphorolysis at 10°C for 10 min resulted in 89% conversion and G4-, G5-, and G6-CNP oligomers were detected in the ratio of 29:26:34%, respectively. The reaction pattern was investigated using an HPLC system. The preparative scale isolation of G(3→6)-CNP glycosides was achieved by size-exclusion column chromatography (SEC) on Toyopearl HW-40 matrix. The productivity of the synthesis was improved by yields of up to 70-75%. Copyright (C) 1999 Elsevier Science Ltd.
A chromogenic assay for limit dextrinase and pullulanase activity
B?jstrup, Marie,Christensen, Caspar Elo,Windahl, Michael Skovbo,Henriksen, Anette,Hindsgaul, Ole
, p. 45 - 51 (2014/02/14)
A new chromogenic substrate to assay the starch debranching enzymes limit dextrinase and pullulanase is described. The 2-chloro-4-nitrophenyl glycoside of a commercially available branched heptasaccharide (Glc-maltotriosyl- maltotriose) was found to be a suitable specific substrate for starch debranching enzymes and allows convenient assays of enzymatic activities in a format suited for high-throughput analysis. The kinetic parameters of these enzymes toward the synthesized substrate are determined, and the selectivity of the substrate in a complex cereal-based extract is established.
Examination of the active sites of human salivary α-amylase (HSA)
Kandra, Lili,Gyemant, Gyoengyi
, p. 579 - 585 (2007/10/03)
The action pattern of human salivary amylase (HSA) was examined by utilising as model substrates 2-chloro-4-nitrophenyl (CNP) β-glycosides of maltooligosaccharides of dp 4-8 and some 4-nitrophenyl (NP) derivatives modified at the nonreducing end with a 4,6-O-benzylidene (Bnl) group. The product pattern and cleavage frequency were investigated by product analysis using HPLC. The results revealed that the binding region in HSA is longer than five subsites usually considered in the literature and suggested the presence of at least six subsites; four glycone binding sites (-4, -3, -2, -1) and two aglycone binding sites (+1, +2). In the ideal arrangement, the six subsites are filled by a glucosyl unit and the release of maltotetraose (G4) from the nonreducing end is dominant. The benzylidene group was also recognisable by subsites (-3) and (-4). The binding modes of the benzylidene derivatives indicated a favourable interaction between the Bnl group and subsite (-3) and an unfavourable one with subsite (-4). Thus, subsite (-4) must be more hydrophylic than hydrophobic. As compared with the action of porcine pancreatic α-amylase (PPA) on the same substrates, the results showed differences in the three-dimensional structure of active sites of HSA and PPA. (C) 2000 Elsevier Science Ltd.
Synthesis of chromogenic substrates of α-amylases on a cyclodextrin basis
Farkas, Erzsebet,Janossy, Lorant,Harangi, Janos,Kandra, Lili,Liptak, Andras
, p. 407 - 415 (2007/10/03)
One-pot acetylation and subsequent partial acetolysis of α-, β-and γ- cyclodextrins resulted in crystalline peracetylated malto-hexaose, -heptaose, and -octaose, respectively. Prolonged acetolysis of β-cyclodextrin gave a mixture of acetylated maltooligosaccharides, from which peracetylated malto- triose, -tetraose, and -pentaose were isolated. The acetylated oligosaccharides were converted into α-acetobromo derivatives, and then transformed into 4-nitrophenyl and 2-chloro-4-nitrophenyl β-glycosides. From the 4-nitrophenyl glycosides 4,6-O-benzylidene derivatives were prepared, which were used together with the free glycosides as substrates of porcine pancreatic α-amylase.