Occurrence of a multimeric high-molecular-weight glyceraldehyde-3-phosphate dehydrogenase in human serum.
J Proteome Res
; 14(4): 1645-56, 2015 Apr 03.
Article
em En
| MEDLINE
| ID: mdl-25734908
ABSTRACT
Cellular glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a phylogenetically conserved, ubiquitous enzyme that plays an indispensable role in energy metabolism. Although a wealth of information is available on cellular GAPDH, there is a clear paucity of data on its extracellular counterpart (i.e., the secreted or extracellular GAPDH). Here, we show that the extracellular GAPDH in human serum is a multimeric, high-molecular-weight, yet glycolytically active enzyme. The high-molecular-weight multimers of serum GAPDH were identified by immunodetection on one- and two-dimensional gel electrophoresis using multiple antibodies specific for various epitopes of GAPDH. Partial purification of serum GAPDH by DEAE Affigel affinity/ion exchange chromatography further established the multimeric composition of serum GAPDH. In vitro data demonstrated that human cell lines secrete a multimeric, high-molecular-weight enzyme similar to that of serum GAPDH. Furthermore, LC-MS/MS analysis of extracellular GAPDH from human cell lines confirmed the presence of unique peptides of GAPDH in the high-molecular-weight subunits. Furthermore, data from pulse-chase experiments established the presence of high-molecular-weight subunits in the secreted, extracellular GAPDH. Taken together, our findings demonstrate the presence of a high-molecular-weight, enzymatically active secretory GAPDH in human serum that may have a hitherto unknown function in humans.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Líquido Extracelular
/
Soro
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Gliceraldeído-3-Fosfato Desidrogenases
Tipo de estudo:
Prognostic_studies
Limite:
Animals
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Humans
Idioma:
En
Revista:
J Proteome Res
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Estados Unidos