Characterization of recombinant L-amino acid deaminase of proteus mirabilis

Abstract

L-amino acid deaminases catalyze the deamination of L-amino acids. Up until now, two types of L-amino acid deaminase have been identified in Proteus species. To investigate enzymatic characteristics of L-amino acid deaminase from Proteus mirabilis, L-amino acid deaminase encoding gene (pmta) was cloned from P. mirabilis T-1. Prokaryotic expression system was established to express recombinant Pmta. Enzymatic characteristics of the enzymes were analyzed. Results showed that recombinant Pmta exhibited function of second type of L-amino acid deaminase. The Km and Vmax value of Pmta for histidine was 10.57 mmol/L and 202.06 μmol/min/mg, respectively. The optimal temperature and pH of recombinant Pmta was 40 °C and 7.0. The enzymatic characteristics of Pmta were different from those of Pm1 discovered in P. mirabilis KCTC, which was probably due to different amino acid sequences. The Pmta deaminase will be very useful in the preparation of commercially valuable materials including urocanic acid and 3-mercaptopyruvic acid.