Monomeric and dimeric cyclomaltodextrinases reveal different modes of substrate degradation
Author
Summary, in English
Two cyclomaltodextrinases (CDase) of thermophilic origin were investigated for their action on cyclodextrins.
Although most CDases known today are made up of at least homodimers, one of the enzymes studied was shown to be a
monomer in solution, while the other one was a dimer. Interestingly, the dimeric enzyme had a much superior selectivity for a cyclodextrin substrate compared to its monomeric homologue, with a specific activity on α-cyclodextrin around 100 times higher than for the polymeric substrates starch and pullulan. Moreover, the monomeric CDase had a 10 times higher activity on those polymers than the dimer. The degradation pattern on cyclodextrins was examined by high-performance
anion-exchange chromatography in combination with microdialysis. The final products were almost exclusively maltose and glucose in an approximate molar ratio of 2:1. However, the intermediate product ratios were quite different for the two enzymes, revealing that the monomeric CDase had a more random distribution of transitional products. Moreover, the dimeric CDase accumulated maltotriose, which is believed to be due to transglycosylation. The oligomeric state of the
enzymes is thought to be a key factor for exhibiting high cyclodextrinase as well as transglycosylation activity.
Although most CDases known today are made up of at least homodimers, one of the enzymes studied was shown to be a
monomer in solution, while the other one was a dimer. Interestingly, the dimeric enzyme had a much superior selectivity for a cyclodextrin substrate compared to its monomeric homologue, with a specific activity on α-cyclodextrin around 100 times higher than for the polymeric substrates starch and pullulan. Moreover, the monomeric CDase had a 10 times higher activity on those polymers than the dimer. The degradation pattern on cyclodextrins was examined by high-performance
anion-exchange chromatography in combination with microdialysis. The final products were almost exclusively maltose and glucose in an approximate molar ratio of 2:1. However, the intermediate product ratios were quite different for the two enzymes, revealing that the monomeric CDase had a more random distribution of transitional products. Moreover, the dimeric CDase accumulated maltotriose, which is believed to be due to transglycosylation. The oligomeric state of the
enzymes is thought to be a key factor for exhibiting high cyclodextrinase as well as transglycosylation activity.
Department/s
Publishing year
2005
Language
English
Pages
79-87
Publication/Series
Biologia
Volume
60
Issue
Suppl. 16
Document type
Journal article
Publisher
Springer
Topic
- Industrial Biotechnology
- Analytical Chemistry
Status
Published
ISBN/ISSN/Other
- ISSN: 0006-3088