alpha-Amylase from the Hyperthermophilic Archaebacterium Pyrococcus furiosus

In this article, Anfinsen, et al, reported that while trying to study the factors that influenced protein thermostability, or the ability to remain stable at relatively high temperatures, they had cloned a gene from the hyperthermophilic bacterium Pyrococcus furiosus encoded with a highly thermostable alpha-amylase and expressed it in Escherichia Coli. The alpha-amylase expressed in E. Coli exhibited the temperature-dependent activation characteristic... of the original enzyme from P. furiosus, but had a higher apparent molecular weight that was attributed to the improper formation of the native quaternary structure.