Proteins with biotechnological potential

The usefulness of thermophilic enzymes in biotechnical applications has been reviewed by several authors [55-57]. The main advantages result from their general high thermostability often combined with a remarkable chemoresistance and a longer shelf life as well as from their ability to catalyze reactions at higher temperature. 

Of potential interest are also the cellulolytic, xylanolytic and pollulan-hydrolyzing activities detected in Thermophilum strains and in AN 1, a member of the Thermococcales [59]. An additional candidate for biotechnical application is also represented by the a-glucosidase from P. furiosus, which exhibits the highest thermostability (to.5(98°C) = 46-48 h) and temperature optimum for activity (105-115 C) compared to all enzymes investigated so far [60] (Table 1). 

Other thermophilic enzymes from archaea may be used for analytical and preparative purposes. For instance, the glucose dehydrogenase from S. solfataricus [70] may serve as a suitable tool for glucose determination, whereas the relatively broad substrate spectrum of the esterase from S. acidocaldarius (catalyzes the acyl transfer to various alcohols and amines [71]) or of the alcohol dehydrogenase from S. solfataricus (oxidizes various aliphatic and aromatic alcohols [72]) makes these enzymes rather attractive for 

Examples of enzymes suitable for use in molecular biology are the DNA polymerases from Thermococcus //torafa[74] and P. fiiriosus 15 With respect to fidelity of the polymerase reaction both enzymes surpass the DNA polymerase from Thermus aquaticus ( Taq polymerase ) currently used for DNA sequencing and DNA amplification (via PCR reaction). 

Not only functional but also structural proteins from archaeal thermophiles are of economic interest. Thus, the S-layer proteins of thermophilic archaea possess some technical potential. As outlined by Sleytr and Sara [76], the S-layers of different members of bacteria are suitable as molecular sieves. The presumed robust S-layers of the hyperthermophilic archaea will certainly enlarge their applicability. 

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One of the major benefits of biotechnology is for the cost effective production of valuable enzymes. In 1987, sales of chymosin alone were a half a billion dollars. Kuraishi (this volume) reports some of the potential applications of transglutaminase, an enzyme recently commercialized by Ajinomoto. The enzyme catalyzes the acyltransfer between the y-carboxyamide group of glutamine and the 8-aminogroup of lysine crosslinking proteins with a e-(y-... 

C. Rausch, A. Lerchner, A. Schiefner, A. Skerra, Crystal structure of the omega-aminotransferase from Paracoccus denitrificans and its phylogenetic relationship with other class III aminotransferases that have biotechnological potential, Proteins 81 (5) (2013) 774-787. 

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