Low-molecular-weight pectate lyase from Streptomyces thermocarboxydus

摘要: An actinomycete producing pectate lyase (PL) isolated from soil was affiliated as Streptomyces thermocarboxydus by 16S rDNA analysis. S. PL I purified to homogeneity two steps of column chromatography the culture filtrate. The molecular mass estimated be 28 kDa SDS-PAGE, and using electrospray ionization spectrometry, it determined 23,897 Da, low-molecular-weight type. amino acid sequence N-terminal 22 residues suggest that enzyme is calcified into Family 3 polysaccharide lyase. optimum pH value 9.0, thermal stabilities were stable up 50°C at a ranging 6 10, respectively. designated an endo-type because detection oligo-galacturonic acids (GalUAs) products initial reaction. Although had little action on highly esterified polygalacturonic methylglycoside, pectin for better substrate than polygalacturonate. For these three substrates, showed maximum activity with addition 0.6 mM Ca2+. acted poly- oligo-GalUAs over di-GalUA larger GalUAs until least DP 8. final both 4,5-unsaturated di- tri-GalUA. This first report thermocarboxydus.