Production and purification of L-phenylalanine oxidase from Morganella morganii.
An enzyme fraction, acting predominantly on L-phenylalanine has been purified and characterized from Morganella morganii. The total envelope was prepared by disrupting the cells with a French press followed by high speed centrifugation. After solubilization of the particulate fraction with 0.1% Triton X-100 and then centrifugation, the resulting supernatant was layered onto a DEAE-Cellulose column. Active fractions eluted were applied to a Phenyl-Sepharose CL-4B column as the final purification step. The activity of the purified enzyme to various L-amino acids in decreasing order was phenylalanine, methionine, leucine, tryptophan, and to a much lesser extent cysteine and tyrosine. At 4 degrees C in 20 mM phosphate buffer pH 7.5, the partially purified fractions collected from the DEAE-Cellulose column were stable for 120 h. On the other hand, the purified fractions obtained from the Phenyl Sepharose CL-4B column showed a drastic decrease in activity within only 24 h. Mg2+ (up to 40 mM), Mn2+ or Ca2+ (up to 10 mM) stimulated the oxidation of the purified enzyme but increases beyond such levels decreased the enzyme activity. Co2+ (0.05 mM), Cu2+ (0.5 mM) or Zn2+ (0.1 mM) decreased the enzyme activity 37, 33 and 20%, respectively.
Gamati
S
S
National Research Council Canada, Biotechnology Research Institute, Montreal, Quebec, Canada.
Luong
J H
JH
D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis / Q000302:isolation & purification*; D004795:Enzyme Stability; D011511:Proteus / Q000201:enzymology*; D011549:Pseudomonas / Q000201:enzymology
D000594:Amino Acid Oxidoreductases; C022342:phenylalanine oxidase