The fructose-1,6-bisphosphate aldolase gene from the thermophilic bacterium, Anoxybacillus gonensis G2, was cloned and sequenced. Nucleotide sequence analysis revealed an open reading frame coding for a 30.9 kDa protein of 286 amino acids. The amino acid sequence shared approximately 80-90% similarity to the Bacillus sp. class II aldolases. The motifs that are responsible for the binding of a divalent metal ion and catalytic activity completely conserved. The gene encoding aldolase was overexpressed under T7 promoter control in Escherichia coli and the recombinant protein purified by nickel affinity chromatography. Kinetic characterization of the enzyme was performed at 60 degrees C, and K(m) and V(max) were found to be 576 microM and 2.4 microM min(-1) mg protein(-1), respectively. Enzyme exhibits maximal activity at pH 8.5. The activity of enzyme was completely inhibited by EDTA.

Polyphenol oxidase (PPO) was purified from Lactarius piperatus (L.) Pers. by using Sepharose 4B‐L‐tyrosine‐p‐amino benzoic acid affinity column. Optimum pH and temperature of purified PPOs of L. piperatus were found to be 7.0 and 20C, respectively, by using catechol as a substrate. The enzyme retained 100% of its original activity at 4C and its optimum pH value for 24 and 72 h. L. piperatus PPO was also quite stable at 20C after 4 h incubation. The Km and Vmax values were calculated as 1 mM and 25 U/mg protein, respectively. Ascorbic acid was found to be the most potent inhibitor for the enzyme. The mushroom PPO was an effective biocatalyst in the selected organic solvents such as dichloromethane, heptane and toluene when using catechin as a substrate. All data support that L. piperatus has a highly active PPO possessing similar biochemical and kinetic characteristics to some plant PPO enzymes. PRACTICAL APPLICATIONS Polyphenol oxidases (PPOs) are a group of copper‐containing enzymes that are widely distributed from bacteria to mammals. Some different mushroom PPOs are subjected to further characterization studies in terms of their biochemical characteristics and their potentials in biotechnological applications. So, purification and characterization studies for PPOs from new sources are very important to explain their biochemical properties and behavior. Thus, one more enzyme may also find applications in food or drug industries.

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