caa a22 4500 37885903X CHVBK 20180305123342.0 cr unu---uuuuu 161128e20031107xx s 000 0 eng 10.1515/BC.2003.158 doi (NATIONALLICENCE)gruyter-10.1515/BC.2003.158 The Catalytically Active Domain in the A Subunit of Calcineurin [Elektronische Daten] [B. Xiang, P. Liu, G. Jiang, K. Zou, F. Yi, S. Yang, Q. Wei] Calcineurin (CaN) is a heterodimer composed of a catalytic subunit A (CaNA) and a regulatory subunit B (CaNB). We report here an active truncated mutation of the rat CaNAδ that contains only the catalytic domain (residues 1-347, also known as a/CaNA). The pnitrophenyl phosphatase activity and protein phosphatase activity of a/CaNA were higher than that of CaNA. Both pnitrophenyl phosphatase activity and protein phosphatase activity of a/CaNA were unaffected by CaM and the B-subunit; the B-subunit and CaM have relatively little effect on pnitrophenyl phosphatase activity and a crucial effect on protein phosphatase activity of CaNA. Mn[2+] and Ni[2+] ions effeciently activated CaNA. The Km of a/CaNA was about 16 mM, and the kcat of a/CaNA was 10.03 1/s using pNPP as substrate. With RII peptide as a substrate, the Km of a/CaNA was about 21 uM and the kcat of a/CaNA was 0.51 1/s. The optimum reaction temperature was about 45C, and the optimum reaction pH was about 7.2. Our results indicate that a/CaNA is the catalytic core of CaNA, and CaN and the Bsubunit binding domain itself might play roles in the negative regulation of the phosphatase activity of CaN. The results provide the basis for future studies on the catalytic domain of CaN. Copyright © 2003 by Walter de Gruyter GmbH & Co. KG Biochemistry nationallicence Molecular biology nationallicence Cellular biology nationallicence Xiang B. aut Liu P. aut Jiang G. aut Zou K. aut Yi F. aut Yang S. aut Wei Q. aut Biological Chemistry Walter de Gruyter 384/10-11(2003-11-07), 1429-1434 1431-6730 384:10-11<1429 2003 384 bchm https://doi.org/10.1515/BC.2003.158 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BC.2003.158 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xiang B. aut NATIONALLICENCE 700 1- Liu P. aut NATIONALLICENCE 700 1- Jiang G. aut NATIONALLICENCE 700 1- Zou K. aut NATIONALLICENCE 700 1- Yi F. aut NATIONALLICENCE 700 1- Yang S. aut NATIONALLICENCE 700 1- Wei Q. aut NATIONALLICENCE 773 0- Biological Chemistry Walter de Gruyter 384/10-11(2003-11-07), 1429-1434 1431-6730 384:10-11<1429 2003 384 bchm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter