TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preparation (Claimed): The dehydrogenase is produced by culturing the transformant and recovering the protein capable of catalyzing dehydrogenation of saccharide from the culture. Preferred Protein: The protein is capable of catalyzing dehydrogenation of reducing sugar other than glucose. The reducing sugar is at least one chosen from maltose, maltotriose, galactose, fructose, xylose and lactose. The protein has Thermus thermophilus derived defined sequence of 352 amino acids (SEQ ID No. 2), given in the specification, or an amino acid sequence comprising one or several amino acid substitution, insertion or addition in SEQ ID No. 2. Preferred Nucleic Acid: The isolated nucleic acid molecule consists of polynucleotide chosen from polynucleotide having a defined sequence of 1059 base pairs (SEQ ID No. 1), given in the specification, and polynucleotide capable of hybridizing under stringent condition with polynucleotide having base sequence of SEQ ID No. 1. EXAMPLE - Genomic DNA of Thermus thermophilus HB8 was isolated. The genomic DNA was used as template and PCR was performed using primers 5'-acattcatatggaccggaggcgctttctcgt-3'(SEQ ID No. 3) (tthgdhf1), 5'-ataccaagcttctaaaggaggcgtagcacccggtc-3'(SEQ ID No. 4) (tthgdhr1) and 5'-ataccaagcttgccaaggaggcgtagcacccggtc-3'(SEQ ID No. 5) (tthgdhr2). The amplified DNA fragment (1 kbp) was purified. The purified fragment and plasmid pET22b were digested with restriction enzymes NdeI and HindIII. The digested fragments were then ligated. The obtained recombinant vector was introduced into Escherichia coli XL1-Blue strain. The transformant was cultured in Luria-Bertani medium containing ampicillin. The single colony on the medium was selected and plasmid was purified. The base sequence of the fragment was determined by chain terminator method. The determined sequence contained 1059 base pairs. The DNA fragment corresponded to base sequence of YP143836, and encoded pyrroloquinoline quinone-dependent glucose dehydrogenase. The gene was transformed into E.coli VL21 (DE3) strain and expressed. The glucose dehydrogenase protein was purified from the culture and analyzed. The protein had molecular weight of 37 kDa when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein had a defined sequence of 352 amino acids (SEQ ID No. 2), given in the specification. The protein had optimum pH of 7 and was stable above 80 degrees C. The protein was capable of utilizing substrate chosen from glucose, galactose, fructose, xylose, lactose, maltose and maltotriose.