Abstract
A maltotetraose- and maltotriose-producing amylase which is stable at alkaline pHs and high temperatures was detected in the culture filtrate of a strain of Chloroflexus aurantiacus J-10-F1, a thermophilic, green, photosynthetic bacterium. The enzyme was purified to homogeneity, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by means of ultrafiltration, ammonium sulfate fractionation, and DEAE-cellulose, hydroxyapatite, and high-performance liquid chromatographies. The molecular mass of the purified enzyme was estimated to be about 210,000 Da. The isoelectric point of the enzyme was estimated to be 6.24 by polyacrylamide gel electrofocusing. The amylase was stable up to 55°C and at alkaline pHs of up to 12.0. The optimum pH and temperature of the enzyme activity were 7.5 and 71°C, respectively. Metal ions such as Hg2+, Zn2+, Cu2+, Mn2+, and Ni2+ strongly inhibited the enzyme activity. The enzyme activity was reactivated specifically by Ca2+ after the enzyme was treated with 1 mM EDTA. This enzyme could digest various kinds of raw-starch granules from corn, cassava, and potato. Both maltotetraose and maltotriose were formed as the main enzymatic products from soluble starch.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Garfin D. E. Isoelectric focusing. Methods Enzymol. 1990;182:459–477. doi: 10.1016/0076-6879(90)82037-3. [DOI] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Pierson B. K., Castenholz R. W. A phototrophic gliding filamentous bacterium of hot springs, Chloroflexus aurantiacus, gen. and sp. nov. Arch Microbiol. 1974;100(1):5–24. doi: 10.1007/BF00446302. [DOI] [PubMed] [Google Scholar]
- Robyt J. F., Ackerman R. J. Isolation, purification, and characterization of a maltotetraose-producing amylase from Pseudomonas stutzeri. Arch Biochem Biophys. 1971 Jul;145(1):105–114. doi: 10.1016/0003-9861(71)90015-4. [DOI] [PubMed] [Google Scholar]
- Strumeyer D. H. A modified starch for use in amylase assays. Anal Biochem. 1967 Apr;19(1):61–71. doi: 10.1016/0003-2697(67)90134-0. [DOI] [PubMed] [Google Scholar]