The bacterial-type phosphoenolpyruvate carboxylase isozyme from developing castor oil seeds is subject to in vivo regulatory phosphorylation at serine-451.
FEBS Lett
; 586(7): 1049-54, 2012 Apr 05.
Article
in En
| MEDLINE
| ID: mdl-22569262
ABSTRACT
Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled anaplerotic enzyme situated at a pivotal branch point of plant carbohydrate-metabolism. In developing castor oil seeds (COS) a novel allosterically-densensitized 910-kDa Class-2 PEPC hetero-octameric complex arises from a tight interaction between 107-kDa plant-type PEPC and 118-kDa bacterial-type PEPC (BTPC) subunits. Mass spectrometry and immunoblotting with anti-phosphoSer451 specific antibodies established that COS BTPC is in vivo phosphorylated at Ser451, a highly conserved target residue that occurs within an intrinsically disordered region. This phosphorylation was enhanced during COS development or in response to depodding. Kinetic characterization of a phosphomimetic (S451D) mutant indicated that Ser451 phosphorylation inhibits the catalytic activity of BTPC subunits within the Class-2 PEPC complex.
Full text:
1
Database:
MEDLINE
Main subject:
Phosphoenolpyruvate Carboxylase
/
Plant Proteins
/
Ricinus
/
Seeds
/
Serine
Language:
En
Journal:
FEBS Lett
Year:
2012
Type:
Article