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Resolution of bovine brain calcineurin subunits: stimulatory effect of subunit B on subunit A phosphatase activity
Author(s) -
Gupta Ramesh C.,
Khandelwal Ramji L.,
Sulakhe Prakash V.
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80437-3
Subject(s) - protein subunit , phosphatase , calcineurin , calmodulin , sephadex , divalent , chemistry , biochemistry , microbiology and biotechnology , biology , enzyme , medicine , organic chemistry , transplantation , gene
Calcineurin was dissociated into subunits A and B by SDS and the dissociated subunits were separated by Sephadex G‐100 column chromatography in SDS. The phosphatase activity was associated with the A subunit and was detected only in the presence of MnCl 2 of the various divalent cations tested. The Mn 2+ ‐dependent phosphatase of A subunit was stimulated (4‐5‐fold) by calmodulin. The subunit B increased only modestly Mn 2+ stimulated phosphatase activity of subunit A but markedly increased it when assay also contained calmodulin. These results support the view that subunit B plays an important role in Mn 2+ /calmodulin regulation of subunit A phosphatase activity. They also lend further support to our earlier postulate ([1984] FEBS Lett. 169, 251‐255) that Mn 2+ is a powerful regulator of calcineurin phosphatase.