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Published on: December 15, 2012
Multiple dextranases from the yeast Lipomyces starkeyi.
Stefan H Millson1, Ivor Howell Evans
1Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
Antonie Van Leeuwenhoek
|June 15, 2007
Summary
The soil yeast Lipomyces starkeyi produces multiple dextranase enzymes. These enzymes, with varying molecular weights and isoelectric points, show conserved N-terminal amino acid sequences.
Area of Science:
- Enzymology
- Microbial Biochemistry
- Glycosyl Hydrolases
Background:
- The soil yeast Lipomyces starkeyi (NCYC 1436) is known to secrete extracellular enzymes.
- Dextranases are enzymes that degrade dextran, a polysaccharide with various industrial applications.
Purpose of the Study:
- To characterize the dextranase activity secreted by Lipomyces starkeyi.
- To resolve and analyze the different molecular forms of the secreted dextranase.
Main Methods:
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to determine molecular weights.
- Isoelectric focusing (IEF) to determine isoelectric points (pIs).
- Amino acid composition analysis and N-terminal sequencing of protein bands.
Main Results:
- Dextranase activity was associated with protein fractions resolved into three bands by SDS-PAGE (66, 68, and 78 kDa).
- Isoelectric focusing resolved the activity into seven distinct protein forms with pIs ranging from 3.50 to 5.30.
- Dextranase activity was confirmed for all isoelectric forms and the 78 kDa species, even in the presence of SDS.
- N-terminal sequencing revealed an alanine-valine pair in the 66 kDa and 78 kDa proteins, consistent with conserved sequences in glycosyl hydrolase family 49.
Conclusions:
- Lipomyces starkeyi secretes multiple dextranase isoforms with distinct physicochemical properties.
- The conserved N-terminal alanine-valine sequence suggests a common evolutionary origin or functional requirement within glycosyl hydrolase family 49.
