Molecular organization of human L' and L pyruvate kinases.
Biochim Biophys Acta
; 709(1): 1-7, 1982 Dec 06.
Article
em En
| MEDLINE
| ID: mdl-6758852
ABSTRACT
Extremities, peptide maps and phosphorylatable site localization of human erythrocyte L' and liver L pyruvate kinases (EC 2.7.1.40) were investigated. L' and L subunits seemed to have similar, blocked NH2 termini and differ in their sensitivity to carboxypeptidase A, that is to say in their C-terminal ends. After digestion by Staphylococcus aureus V8 protease, the phosphorylated sites of both L' and L subunits were located on those peptides which were different in L' and L, that is to say on the C-terminal sides. A mild proteolytic attack of the native tetrameric enzymes by trypsin partially degraded the phosphorylatable peptides without removing the phosphoserine residue; in the same conditions, chymotrypsin split off this phosphorylated residue and subtilisin totally degraded the phosphorylated peptides. From these results it appears, therefore, that age-dependent proteolytic degradation of L' subunits in old red cells involves the C-terminal side of the molecules, ultimately resulting in cleavage of the phosphorylated site. Since erythrocyte L' and liver L subunits are encoded by different species of messenger RNAs, our results indicate, in addition, that these messenger RNA species should differ by their 3' coding sequences.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Piruvato Quinase
/
Serina Endopeptidases
Limite:
Humans
Idioma:
En
Ano de publicação:
1982
Tipo de documento:
Article