Investigation of the substrate specificity of glutamyl endopeptidase using purified bovine ß-casein and synthetic peptides.
J Agric Food Chem
; 61(13): 3193-204, 2013 Apr 03.
Article
em En
| MEDLINE
| ID: mdl-23473379
ABSTRACT
Purified bovine ß-casein was digested with glutamyl endopeptidase (GE) at 37 and 50 °C for 4 h. The peptides generated were determined using nano-LC-ESI-qTOF-MS/MS. GE was highly specific and hydrolyzed peptide bonds in ß-casein predominantly on the carboxy terminal of Glu and Asp. Pro residues were not preferred, while Met was poorly preferred at the P1' position. Glu-Met hydrolysis was less preferred in comparison to Asp-Met hydrolysis. Five synthetic peptides corresponding to specific sequences in ß-casein were incubated with GE at 37 °C to further characterize the substrate specificity. MS analysis of the digestion products indicated that GE hydrolyzed Glu-Ser in Glu-Glu-Ser. Furthermore, hydrolysis of Glu-Met and Glu-Pro was observed. The presence of multiple-phosphorylated Ser residues upstream from the scissile bond did not appear to affect hydrolysis of Glu-Ser. The results herein are relevant to our understanding of the substrate specificity of GE and the peptides that may be expected during the hydrolysis of ß-casein.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Serina Endopeptidases
/
Caseínas
Limite:
Animals
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article