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C‐terminal labelling of β‐casein
Author(s) -
Carles Christophe,
Gueguen Paul,
Ribadeau-Dumas Bruno
Publication year - 1987
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 - 10.1016/0014-5793(87)81578-8
Subject(s) - labelling , terminal (telecommunication) , casein , chemistry , biochemistry , computer science , telecommunications
This paper is the first to report specific labelling of a native protein at its C‐terminal end by carboxypeptidase Y‐catalyzed transpeptidation between β‐casein and tritiated Phe amide. A tryptic digest of the radiolabelled protein was resolved by reversed‐phase HPLC and a single labelled peptide was isolated therefrom. Sequence determination and FAB mass spectrometry showed that the last 2 residues (Val‐209, Ile‐208) of β‐casein had been deleted and Ile 207 substituted by Phe, deamidation presumably occurring after transpeptidation. Identical results were obtained by transpeptidating the isolated C‐terminal tryptic heptapeptide (203–209) of native β‐casein.