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Novel GTP‐binding proteins in plasma membranes and zymogen granule membranes from rat pancreas and in pancreatic AR 4‐2J cell membranes
Author(s) -
Lambert Monique,
Bui Ngoc-Diem,
Christophe J.
Publication year - 1990
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(90)80362-m
Subject(s) - membrane , gtp' , zymogen , biochemistry , chemistry , enzyme
Photoaffinity labelling with [α‐ 32 P]GTP allowed to detect a 54 kDa GTP‐binding protein in rat pancreatic plasma membranes and in pancreatic AR 4‐2J cell membranes. Like the 42 and 48 kDa G s α subunits and the 41 kDa G i α subunit, this protein was absent from zymogen granule membranes. Contrastingly, a new 28 kDa GTP‐binding protein (detected by [α‐ 32 P]GTP binding on immobilized proteins) and a 25 kDa protein (ADP‐ribosylated by botulinum toxin D) were found in all three membrane preparations. This is to our knowledge the first report on GTP‐binding proteins in zymogen granule membranes.