Partial purification and characterization of an enzyme from pea nuclei with protein tyrosine phosphatase activity.
AUTOR(ES)
Guo, Y L
RESUMO
A pea (Pisum sativum L.) nuclear enzyme with protein tyrosine phosphatase activity has been partially purified and characterized. The enzyme has a molecular mass of 90 kD as judged by molecular sieve column chromatography and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Like animal protein tyrosine phosphatases it can be inhibited by low concentrations of molybdate and vanadate. It is also inhibited by heparin and spermine but not by either the acid phosphatase inhibitors citrate and tartrate or the protein serine/threonine phosphatase inhibitor okadaic acid. The enzyme does not require Ca2+, Mg2+, or Mn2+ for its activity but is stimulated by ethylenediaminetetraacetate and by ethyleneglycolbis(beta-aminoethyl ether)-N,N'-tetraacetic acid. It dephosphorylates phosphotyrosine residues on the four different 32P-tyrosine-labeled peptides tested but not the phosphoserine/threonine residues on casein and histone. Like some animal protein tyrosine phosphatases, it has a variable pH optimum depending on the substrate used: the optimum is 5.5 when the substrate is [32P]tyrosine-labeled lysozyme, but it is 7.0 when the substrate is [32P]tyrosine-labeled poly(glutamic acid, tyrosine). It has a Km of 4 microM when the lysozyme protein is used as a substrate.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=161180Documentos Relacionados
- Acid phosphatase purified from Mycoplasma fermentans has protein tyrosine phosphatase-like activity.
- Purification and Characterization of a Potato Tuber Acid Phosphatase Having Significant Phosphotyrosine Phosphatase Activity.
- Partial Purification and Characterization of Two Peptide Hydrolases from Pea Seeds
- Epidermal growth factor stimulates substrate-selective protein-tyrosine-phosphatase activity.
- Purification and characterization of an active fragment of the LasA protein from Pseudomonas aeruginosa: enhancement of elastase activity.