Purification and characterization of the extracellular alpha-amylase from Streptococcus bovis JB1.
AUTOR(ES)
Freer, S N
RESUMO
The extracellular alpha-amylase (1,4-alpha-D-glucanglucanohydrolase; EC 3.2.1.1) from maltose-grown Streptococcus bovis JB1 was purified to apparent homogeneity by ion-exchange chromatography (Mono Q). The enzyme had an isoelectric point of 4.50 and an apparent molecular mass of 77,000 Da, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was rich in acidic and hydrophobic amino acids. The 15-amino-acid NH2-terminal sequence was 40% homologous with the Bacillus subtilis saccharifying alpha-amylase and 27% homologous with the Clostridium acetobutylicum alpha-amylase. alpha-Amylase activity on soluble starch was optimal at pH 5.0 to 6.0. The enzyme was relatively stable between pH 5.5 and 8.5 and at temperatures below 50 degrees C. When soluble potato starch was used as the substrate, the enzyme had a Km of 0.88 mg.ml-1 and a kcat of 2,510 mumol of reducing sugar.min-1.mg of protein-1. The enzyme exhibited neither pullulanase nor dextranase activity and was 40 to 70% as active on amylopectin as on amylose. The major end products of amylose hydrolysis were maltose, maltotriose, and maltotetraose.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=182095Documentos Relacionados
- Purification, characterization, and nucleotide sequence of an intracellular maltotriose-producing alpha-amylase from Streptococcus bovis 148.
- Purification and characterization of the extracellular alpha-amylase from Clostridium acetobutylicum ATCC 824.
- Purification and characterization of an extracellular alpha-amylase from Clostridium perfringens type A.
- Production, purification, and characterization of alpha-amylase from Thermomonospora curvata.
- Purification and some properties of an extracellular alpha-amylase from Bacteroides amylophilus.