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Purification and characterization of copper‐metallothionein from Aspergillus niger by affinity chromatography
Author(s) -
Goetghebeur M.,
Kermasha S.,
Kensley J.,
Metche M.
Publication year - 1995
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.1470-8744.1995.tb00354.x
Subject(s) - metallothionein , aspergillus niger , affinity chromatography , copper , chemistry , chromatography , biochemistry , enzyme , zinc , organic chemistry
Biomass of Aspergillus niger was obtained from a microbial culture and a copper (Cu) induction was performed after 72 h of fermentation. The crude induced metallothionein extract was obtained by cell disruption and partly purified by a heat treatment and ultrafiltration. The purification of metallothionein by affinity chromatography resulted in three major fractions: FIVa, FIVb and FIVc3. Cu analysis demonstrated that only fraction FIVc contained the Cu‐metallothionein. Spectrophotometric analyses of FIVc demonstrated the presence of a peak at 259 nm and a ratio of 78 mol of Cu per mol of protein. Electrophoretic analyses of FIVc, performed under denaturing conditions, showed the presence of one band with molecular mass of 21 kDa; however, two isoforms were observed under native conditions with molecular masses of 9.5 and 10.5 kDa and isoelectric points of 6.2 and 6.5, suggesting a recombination process due to denaturation.