Purification and characterization of L-arginine deiminase from Penicillium chrysogenum

L-arginine deiminase (ADI, EC 3.5.3.6) hydrolyzes arginine to ammonia and citrulline which is a natural supplement in health care. ADI was purified from Penicillium chrysogenum using 85% ammonium sulfate, DEAE-cellulose and Sephadex G₂₀₀. ADI was purified 17.2-fold and 4.6% yield with a specific activity of 50 Umg^- 1 protein. The molecular weight was 49 kDa. ADI expressed maximum activity at 40^oC and an optimum pH of 6.0. ADI thermostability was investigated and the values of both t_0.5 and D were determined. K_d increased by temperature and the Z value was 38^oC. ATP, ADP and AMP activated ADI up to 0.6 mM. Cysteine and dithiothreitol activated ADI up to 60 µmol whereas the activation by thioglycolate and reduced glutathione (GSH) prolonged to 80 µmol. EDTA, α,α-dipyridyl, and o-phenanthroline inactivated ADI indicating that ADI is a metalloenzyme. N-ethylmaleimide (NEM), N-bromosuccinimide (NBS), butanedione (BD), dansyl chloride (DC), diethylpyrocarbonate (DEPC) and N-acetyl-imidazole (NAI) inhibited ADI activity indicating the necessity of sulfhydryl, tryptophanyl, arginyl, lysyl, histidyl and tyrosyl groups, respectively for ADI catalysis. The obtained results show that ADI from P. chrysogenum could be a potential candidate for industrial and biotechnological applications.