ABSTRACT
Phenylalanine ammonia-lyase is the first enzyme of general phenylpropanoid pathway. A PAL gene, designated as BoPAL1, was cloned from a Bambusa oldhamii cDNA library. The open reading frame of BoPAL1 was 2,139 bp in size and predicted to encode a 712-amino acid polypeptide. BoPAL1 was the first intronless PAL gene found in angiosperm plant. Several putative cis-acting elements such as P box, GT-1motif, and SOLIPs involved in light responsiveness were found in the 5'-flanking sequence of BoPAL1 which was obtained by TAIL-PCR method. Recombinant BoPAL1 protein expressed in Pichia pastoris was active. The optimum temperature and pH for BoPAL1 activity was 50°C and 9.0, respectively. The molecular mass of recombinant BoPAL1 was estimated as 323 kDa using gel filtration chromatography and the molecular mass of full-length BoPAL was about 80 kDa, indicating that BoPAL1 presents as a homotetramer. The Km and kcat values of BoPAL1 for L-Phe were 1.01 mM and 10.11 s(-1), respectively. The recombinant protein had similar biochemical properties with PALs reported in other plants.
Subject(s)
Bambusa/enzymology , Bambusa/genetics , Genes, Plant/genetics , Phenylalanine Ammonia-Lyase/genetics , Plant Proteins/genetics , 5' Flanking Region/genetics , Base Sequence , Chromatography, Affinity , Cloning, Molecular , Kinetics , Models, Molecular , Molecular Sequence Data , Phenylalanine Ammonia-Lyase/chemistry , Pichia/metabolism , Plant Proteins/chemistry , Recombinant Proteins/isolation & purification , Regulatory Sequences, Nucleic Acid/genetics , Species SpecificityABSTRACT
Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) is the first committed enzyme of phenylpropanoid pathway. A PAL gene, designated as BoPAL2, was cloned from a Bambusa oldhamii cDNA library. The open reading frame of BoPAL2 was 2142bp in size encoding a 713-amino acid polypeptide. BoPAL2 was heterologous expressed in Escherichia coli and Pichia pastoris. The recombinant proteins were exhibited PAL and tyrosine ammonia-lyase activities. The recombinant BoPAL2 had a subunit mass of 80kDa and existed as a homotetramer. The optimum temperature and pH of BoPAL2 were 50-60 degrees C and 8.5-9.0, respectively. The K(m) and k(cat) values of BoPAL2 expressed in E. coli were 250microM and 10.12s(-1). The K(m) and k(cat) values of BoPAL2 expressed in P. pastoris were 331microM and 16.04s(-1). The recombinant proteins had similar biochemical properties and kinetic parameters with PALs reported in other plants.
