Abstract
Orthovanadate is known to be an inhibitor of protein tyrosine phosphatases. However, we found that it inhibited calcineurin which has the activity of a serine/threonine protein phosphatase, using casein phosphorylated by cyclic AMP-dependent protein kinase as a substrate. Orthovanadate inhibits the Mn2+-activated activity of purified calcineurin to 20%; this is not the case without Mn2+. Furthermore, 10 mM dithiothreitol (DTT) reversed the inhibitory effects of orthovanadate. Orthovanadate showed the same inhibitory effect for calcineurin activity in homogenates as for the purified enzyme; the inhibitory effect was reversed by DTT. These results indicate that orthovanadate inhibits not only protein tyrosine phosphatases as reported, but also serine/threonine phosphatase activity of calcineurin.
Original language | English |
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Pages (from-to) | 342-345 |
Number of pages | 4 |
Journal | Biochemical and biophysical research communications |
Volume | 253 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1998 Dec 18 |
Externally published | Yes |
Keywords
- Calcineurin
- Sodium orthovanadate
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology