TY - JOUR
T1 - Identification of the pH-dependent membrane anchor of carboxypeptidase E (EC 3.4.17.10)
AU - Fricker, Lloyd D.
AU - Das, Banasree
AU - Angeletti, Ruth Hogue
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1990
Y1 - 1990
N2 - Carboxypeptidase E (CPE), a peptide hormone-processing enzyme, is present within secretory granules in both a soluble form and a form which is membrane-bound at pH 5.5 but soluble at neutral pH. Antisera raised against a peptide corresponding to the predicted COOH-terminus of CPE bind to the membrane-associated form of CPE but not to the soluble form. This COOH-terminal region is predicted to form an amphiphilic α-helix, containing several pairs of hydrophobic residues separated by hydrophilic residues. Synthetic COOH-terminal peptides 11-24 residues in length are able to bind to bovine pituitary membranes and can be extracted by conditions that extract the membrane-bound form of CPE. The influence of pH on the membrane binding of a 21-residue COOH-terminal peptide is similar to the membrane binding of CPE: at pH values < 6 the majority of the peptide is membrane-bound, while at pH values above 8 less than 20% is membrane-bound. Both the 21-residue COOH-terminal peptide and the purified membrane form of CPE, but not the soluble form, partition into Triton X-114 only at low pH (pH < 6). Combined polar and hydrophobic interactions of the COOH-terminal peptide appear to be responsible for the reversible, pH-dependent association of CPE with membranes.
AB - Carboxypeptidase E (CPE), a peptide hormone-processing enzyme, is present within secretory granules in both a soluble form and a form which is membrane-bound at pH 5.5 but soluble at neutral pH. Antisera raised against a peptide corresponding to the predicted COOH-terminus of CPE bind to the membrane-associated form of CPE but not to the soluble form. This COOH-terminal region is predicted to form an amphiphilic α-helix, containing several pairs of hydrophobic residues separated by hydrophilic residues. Synthetic COOH-terminal peptides 11-24 residues in length are able to bind to bovine pituitary membranes and can be extracted by conditions that extract the membrane-bound form of CPE. The influence of pH on the membrane binding of a 21-residue COOH-terminal peptide is similar to the membrane binding of CPE: at pH values < 6 the majority of the peptide is membrane-bound, while at pH values above 8 less than 20% is membrane-bound. Both the 21-residue COOH-terminal peptide and the purified membrane form of CPE, but not the soluble form, partition into Triton X-114 only at low pH (pH < 6). Combined polar and hydrophobic interactions of the COOH-terminal peptide appear to be responsible for the reversible, pH-dependent association of CPE with membranes.
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M3 - Article
C2 - 2303412
AN - SCOPUS:0025327208
SN - 0021-9258
VL - 265
SP - 2476
EP - 2482
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 5
ER -