Abstract

The 2-deoxy-D-ribose-5-phosphate aldolase gene from Thermococcus onnurineus NA1was sub cloned, over expressed in Escherichia coli and purified to apparent homogeneity. Analysis of the sequence of gene revealed an n of 681 base pairs encoding 227 amino acids predicted to yield a protein having molecular mass 25.3 kDa. The enzyme activity was optimal at 60°C and showed broad temperature adaptability, retaining more than 30% of its maximum activity when assayed at 10 to 75°C. The recombinant protein was heat stable; no activity loss was observed even after incubation at 80°C for 10 min. In addition, the thermophilic enzyme showed a remarkable resistance to acetaldehyde; it retained more than 45% activity after exposure for 20 h to 250 mM acetaldehyde at 25°C.

Key words: 2-Deoxy-D-ribose-5-phosphate aldolase, thermostable enzyme, broad temperature adaptability.