Action pattern of porcine pancreatic alpha-amylase on three different series of beta-maltooligosaccharide glycosides.
A technique for the investigation of the action pattern of porcine pancreatic amylase (PPA) has been developed by utilising as model substrates 2-chloro-4-nitrophenyl (CNP) and 4-nitrophenyl (NP) beta-glycosides of maltooligosaccharides of dp 4-8 and some NP derivatives modified at the nonreducing end with a 4,6-O-benzylidene (Bnl) group. The action pattern was investigated by the method of product analysis, using an HPLC method. The product pattern and cleavage frequency was very similar in the CNP- and NP-oligomers and showed that the glucopyranose residue could be replaced by the aglycon group. Modification of the nonreducing end of NP glycosides to give a 4,6-O-benzylidene-D-glucopyranosyl group indicated a favourable interaction between the Bnl group and the subsites (-3) and (-5) but an unfavourable one with subsite (-4), which resulted in a clear shift in the product pattern. The results obtained with the digestion of the benzylidene-protected substrates confirm a multiple attack mechanism for PPA.
Kandra
L
L
Institute of Biochemistry, L. Kossuth University, Debrecen, Hungary.
Gyémánt
G
G
Farkas
E
E
Lipták
A
A
D000818:Animals; D001665:Binding Sites; D006027:Glycosides / Q000378:metabolism*; D006868:Hydrolysis; D009578:Nitrobenzenes; D009844:Oligosaccharides / Q000378:metabolism*; D010179:Pancreas / Q000201:enzymology*; D013237:Stereoisomerism; D013379:Substrate Specificity; D013552:Swine; D000516:alpha-Amylases / Q000378:metabolism*
D006027:Glycosides; D009578:Nitrobenzenes; D009844:Oligosaccharides; C021705:maltooligosaccharides; D000516:alpha-Amylases