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Acarbose 7-phosphotransferase from Actinoplanes sp.: purification, properties, and possible physiological function
The Journal of Antibiotics
|July 1, 1996
Summary
Researchers isolated a novel phosphotransferase enzyme from the acarbose-producing bacterium Actinoplanes sp. This enzyme phosphorylates acarbose, reducing its inhibitory effect on disaccharidases, suggesting a self-defense mechanism.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Acarbose is an alpha-glucosidase inhibitor used to treat type 2 diabetes.
- The producing organism, Actinoplanes sp., must possess mechanisms to protect itself from its own antibiotic production.
Purpose of the Study:
- To isolate and characterize the enzyme responsible for modifying acarbose in Actinoplanes sp.
- To investigate the biochemical properties and specificity of this enzyme.
- To elucidate the potential role of this enzyme in the producing organism's self-defense.
Main Methods:
- Isolation and purification of the phosphotransferase enzyme.
- Determination of the enzyme's N-terminal amino acid sequence.
- Enzyme activity assays using acarbose and related compounds.
- Analysis of the inhibitory activity of acarbose and its phosphorylated product on disaccharidases and maltase.
Main Results:
- A homogeneous ATP-dependent phosphotransferase, acarbose 7-phospho-transferase, was isolated.
- The enzyme specifically phosphorylates acarbose at the 7-position to form acarbose-7-phosphate.
- Acarbose-7-phosphate exhibits significantly reduced inhibitory activity against disaccharidases and maltase compared to acarbose.
Conclusions:
- Acarbose 7-phospho-transferase modifies acarbose, decreasing its biological activity.
- This enzymatic modification likely serves as a self-defense mechanism for Actinoplanes sp. against acarbose.
- The findings provide insight into microbial antibiotic resistance and biosynthesis pathways.