Characterization of a novel endopolygalacturonase from Aspergillus niger with unique kinetic properties.
We isolated and characterized a new type of endopolygalacturonase (PG)-encoding gene, pgaD, from Aspergillus niger. The primary structure of PGD differs from that of other A. niger PGs by a 136 amino acid residues long N-terminal extension. Biochemical analysis demonstrated extreme processive behavior of the enzyme on oligomers longer than five galacturonate units. Furthermore, PGD is the only A. niger PG capable of hydrolyzing di-galacturonate. It is tentatively concluded that the enzyme is composed of four subsites. The physiological role of PGD is discussed.
Parenicová
L
L
Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreyenlaan 2, 6703 HA, Wageningen, The Netherlands.
Kester
H C
HC
Benen
J A
JA
Visser
J
J
D001234:Aspergillus niger / Q000201:enzymology* / Q000235:genetics; D001665:Binding Sites; D004187:Disaccharides / Q000378:metabolism; D007526:Isoelectric Point; D007700:Kinetics; D008970:Molecular Weight; D011096:Polygalacturonase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D013400:Sugar Acids / Q000378:metabolism
D004187:Disaccharides; D013400:Sugar Acids; D011096:Polygalacturonase; C090179:digalacturonic acid