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Purification and characterization of polygalacturonases produced by the hyphal fungus Aspergillus niger
Author(s) -
Kester HC,
Visser J.
Publication year - 1990
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1111/j.1470-8744.1990.tb00088.x
Subject(s) - chromatofocusing , pectinase , isoelectric point , aspergillus niger , chemistry , gel permeation chromatography , chromatography , biochemistry , affinity chromatography , molecular mass , enzyme , organic chemistry , polymer
Five endo‐polygalacturonases (poly(1,4‐alpha‐D‐galacturonide) glycanohydrolase, EC 3.2.1.15) and one exo‐polygalacturonase (poly(1,4‐alpha‐D‐galacturonide) galacturonohydrolase, EC 3.2.1.67) were isolated from a commercial pectinase preparation derived from Aspergillus niger. All five endo‐enzymes could be purified to homogeneity by affinity chromatography on cross‐linked alginate, ion‐exchange chromatography, chromatofocusing, and gel permeation chromatography. The exo‐polygalacturonase was only partially purified but free from endo‐polygalacturonase activity. The two most abundant endo‐polygalacturonases (endo‐I and endo‐II), with molecular masses of 55 and 38 kDa, respectively, are quite different with respect to their isoelectric point, specific activity, mode of action on oligomeric substrates, and amino acid composition. The physicochemical properties of the other three endo‐polygalacturonases (endo‐IIIA, endo‐IIIB, and endo‐IV), present in low amounts, are quite similar to those of the endo‐I type. The pH optima of all these endo‐polygalacturonases are in the range of 4.3–4.9.