• The Korean Journal of Food And Nutrition
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• v.7 no.4
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• pp.259-266
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• 1994

The hyperthermophilic archaebacterium Thermococcus profundus Isolated from a deep-sea hydrothermal vent system, produced several amylolytic enzymes such as extracellular amylase and pullulanase, intracellular a-1,4-91ucosidase in respone to the presence of complex carbohydrates In the growth medium. This strain showed high activities on 0.5% maltose than on complex carbohydrates One of the amylases was partially purified by ammonium sulfate precipitation, DEAE-Toyopearl chromatography. The amylase exhibited maximal activity at pH 5.5 and 80$^{\circ}C$, and was stable in the range of pH 5.5 to 9.5 and up to 80$^{\circ}C$ for 30 min. The enzyme activity was no dependence on Ca2+ and not inhibited by detergents. The amylase hydrolyzed soluble starch, amylose, amylopectin and glycogen to produce maltose and maltotriose with trace amounts of glucose, but not pullulan and ${\alpha}$-, ${\beta}$-, ${\gamma}$-cyclodextrin. Malto-oligosaccharides ranging from maltotetraose to maltoheptaose were hydrolyzed in an endo fashion.

• Applied Microscopy
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• v.30 no.4
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• pp.413-421
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• 2000

We have isolated a large cylindrical protein complex from hyperthermophile archaeon Thermococcus profundus. Structural analysis by image processing of electron micrographs suggests that the complex is composed of two stacked rings of eight subunits each; the ring enclose a central channel. The purified protein was shown to be a homomultimer of 60 kDa subunit (P60 complex). It exhibits an extremely thermostable ATPase activity with a temperature optimum of $80^{\circ}C$. This protein complex may play an important role in the adaptation of thermophile archaeon to life at high temperature.

• Applied Microscopy
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• v.30 no.2
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• pp.185-191
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• 2000

An unusually large protein complex was found in the cytosol of the hyperthmophilic archaeon. Thermococcus profundus. The purified protein was shown to be a homomultimer of 93 kDa subunit (P93 complex). The complex is extremely heat stable. During 12 hrs incubation with SDS (final concentration 1%) at $85^{\circ}C$, no changed structure could be observed. Electron image analysis of negatively stained showed that the complex has a single, stable characteristic view and a well-preserved core with threefold rotational symmetry. The periphery of the assembly is composed of a nebulose, possibly flexible, component. Based on the projected structure suggest the P93 complex from T. profundus is composed 24 homomultimer.