ISSN:
1432-0983
Keywords:
Aspergillus niger
;
Invertase
;
Purification
;
Sequence
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A secreted invertase was purified 23-fold by ultrafiltration, ion-exchange, and gel filtration chromatography from the culture supernatant of 18h sucrose-grown cultures of Aspergillus niger. The purified enzyme hydrolysed sucrose and raffinose but there was no detectable hydrolysis of inulin, melezitose or PNPG. Invertase activity was optimal at pH 5.5 and 50°C. The molecular mass of reduced invertase was 115 kDa, as determined by SDS gel electrophoresis. The native molecular weight of between 225 kDa and 250 kDa, estimated by electrophoresis under non-denaturing conditions, suggests that the protein is a dimer of identical subunits. The suc1 gene encoding this protein was completely sequenced. The translated sequence yields a protein of 566 amino acids with a calculated molecular mass of 61 kDa, suggesting that carbohydrates represent about 50% of the mass of the protein.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00324666
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