A second form of phenylalanine ammonia-lyase from leaf mustard.
Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) catalyzes the elimination of ammonium ion from L-phenylalanine in a variety of plants and fungal species. PAL was previously purified and characterized from leaf mustard in our laboratory. In the present study, we purified a second phenylalanine ammonia-lyase (PAL II) from leaf mustard by a combination of ion exchange chromatography and gel filtration. PAL I and PAL II migrate at a different rate on native polyacrylamide gel electrophoresis. It consists of four subunits, each having the molecular mass of about 37,000 Da. Its isoelectric point and Km value for L-phenylalanine were found to be 5.4 and 3.8 x 10(-5)M, respectively. The purified enzyme has an optimum pH and temperature of 8 and 45 degree C, respectively. It is activated about 2-fold by caffeic acid (1 mM), whereas it is inhibited to 15% by Zn2+ (1 mM). However, the physiological role of PAL II remains unknown.
Division of Life Sciences, College of Natural Sciences, Kangwon National University, Chuncheon, Korea.
H W
HW
Lim
J H
JH
Sa
S S
SS
Park
C J
CJ
Lim
D000596:Amino Acids / Q000737:chemistry; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008670:Metals / Q000737:chemistry; D008970:Molecular Weight; D009149:Mustard Plant / Q000737:chemistry / Q000201:enzymology*; D010650:Phenylalanine Ammonia-Lyase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000201:enzymology*; D010946:Plants, Medicinal; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
D000596:Amino Acids; D006841:Hydrocarbons, Aromatic; D007527:Isoenzymes; D008670:Metals; D013438:Sulfhydryl Compounds; D010650:Phenylalanine Ammonia-Lyase