Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.4.16.2 (
PCP
)
3,761
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Three phosphatases active on phosphocasein (PhosphoCasein Phosphatases) termed
PCP
-I,
PCP
-II and
PCP
-III were isolated from maize seedlings by DEAE-cellulose chromatography and were shown to display a different specificity toward a variety of phosphorylated substrates including pNPP, phosphohistones, phosphorylase a and several phosphopeptides containing either phosphoserine or phosphothreonine.
PCP
-I and
PCP
-II bind to heparin-Sepharose, retain a remarkable pNPP activity, are uncapable to dephosphorylate phosphorylase a, and display striking activity toward the acidic phosphopeptide AS[32P]EEEEE. They also by far prefer phosphoseryl peptide
RRAS
[32P]VA over its phosphothreonyl derivative and are unsensitive to okadaic acid up to 1 microM. These properties are not consistent with the belonging of
PCP
-I and -II to any of the known classes of protein phosphatases and suggest that they are acidic phosphatases. Conversely,
PCP
-III is essentially free of pNPP activity; it readily dephosphorylates phosphohistone H1 and phosphorylase a and it displays a striking preference toward the phosphothreonyl peptides (RRAT[32P]VA and RRREEET[32P]EEEAA), while the phosphoseryl peptides (
RRAS
[32P]VA and AS[32P]EEEEE) are very poor substrates of the enzyme. These properties together with the findings that
PCP
-III does not bind to heparin-Sepharose and is highly sensitive to okadaic acid (IC50 = 0.2 nM) allow to identify
PCP
-III with a protein phosphatase of the PP-2A class.
...
PMID:Identification of protein phosphatase activities in maize seedlings. 131 1
