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Regulatory phosphorylation of plant phospho enol pyruvate carboxylase: role of a conserved basic residue upstream of the phosphorylation site
Author(s) -
Ueno Yoshihisa,
Hata Shingo,
Izui Katsura
Publication year - 1997
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/s0014-5793(97)01254-4
Subject(s) - phosphorylation , residue (chemistry) , biochemistry , pyruvate carboxylase , chemistry , enzyme
In order to mimic regulatory phosphorylation of the Ser‐15 of maize C 4 ‐form phospho enol pyruvate carboxylase (PEPC), we replaced Ser‐15 and Lys‐12 with Asp (S15D) and Asn (K12N), respectively, by site‐directed mutagenesis. Although both mutant enzymes were catalytically as active as the wild‐type PEPC, they showed much less sensitivity to malate, an allosteric inhibitor, similarly to the phosphorylated wild‐type PEPC. A maize protein kinase of 30 kDa which is known to be specific to PEPC (PEPC‐PK), phosphorylated K12N as well as the wild‐type PEPC but not S15D. The phosphorylation of K12N further diminished the sensitivity to malate. Thus, a positive charge of the conserved Lys‐12 is not required for the recognition by PEPC‐PK but contributes to the intrinsic sensitivity to malate inhibition.