Purification and characterization of a soluble calnexin from human placenta

Dorthe T Olsen, Li Peng, Sofie D Træholt, Karen Duus, Peter Højrup, Gunnar Houen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Calreticulin (Crt) and calnexin (Cnx) are homologous endoplasmic reticulum (ER) chaperones involved in protein folding and quality control. Crt is a soluble ER luminal Mr 46 kDa protein and Cnx is a Mr 67kDa ER membrane protein. During purification of Crt from human placenta a soluble form of Cnx (sCnx) was consistently identified in a separate ion exchange chromatography peak. The sCnx was further purified and characterised. This showed that the protein had been cleaved after residue 472 (between Gln and Met), thus liberating it from the transmembrane and cytoplasmic parts of Cnx. The extraction and initial purification steps were carried out in the presence of protease inhibitors, thus ruling out that the cleavage was an artefact of the isolation procedure. This indicates that sCnx may have a physiological chaperone function similar to that of Crt.
Original languageEnglish
JournalProtein Expression and Purification
Volume92
Issue number1
Pages (from-to)105-11
ISSN1046-5928
DOIs
Publication statusPublished - 2013

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Calnexin
Calreticulin
Placenta
Ion Exchange Chromatography
Protease Inhibitors
Artifacts
Membrane Proteins
Proteins

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Olsen, Dorthe T ; Peng, Li ; Træholt, Sofie D ; Duus, Karen ; Højrup, Peter ; Houen, Gunnar. / Purification and characterization of a soluble calnexin from human placenta. In: Protein Expression and Purification. 2013 ; Vol. 92, No. 1. pp. 105-11.
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abstract = "Calreticulin (Crt) and calnexin (Cnx) are homologous endoplasmic reticulum (ER) chaperones involved in protein folding and quality control. Crt is a soluble ER luminal Mr 46 kDa protein and Cnx is a Mr 67kDa ER membrane protein. During purification of Crt from human placenta a soluble form of Cnx (sCnx) was consistently identified in a separate ion exchange chromatography peak. The sCnx was further purified and characterised. This showed that the protein had been cleaved after residue 472 (between Gln and Met), thus liberating it from the transmembrane and cytoplasmic parts of Cnx. The extraction and initial purification steps were carried out in the presence of protease inhibitors, thus ruling out that the cleavage was an artefact of the isolation procedure. This indicates that sCnx may have a physiological chaperone function similar to that of Crt.",
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Purification and characterization of a soluble calnexin from human placenta. / Olsen, Dorthe T; Peng, Li; Træholt, Sofie D; Duus, Karen; Højrup, Peter; Houen, Gunnar.

In: Protein Expression and Purification, Vol. 92, No. 1, 2013, p. 105-11.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Purification and characterization of a soluble calnexin from human placenta

AU - Olsen, Dorthe T

AU - Peng, Li

AU - Træholt, Sofie D

AU - Duus, Karen

AU - Højrup, Peter

AU - Houen, Gunnar

N1 - Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

PY - 2013

Y1 - 2013

N2 - Calreticulin (Crt) and calnexin (Cnx) are homologous endoplasmic reticulum (ER) chaperones involved in protein folding and quality control. Crt is a soluble ER luminal Mr 46 kDa protein and Cnx is a Mr 67kDa ER membrane protein. During purification of Crt from human placenta a soluble form of Cnx (sCnx) was consistently identified in a separate ion exchange chromatography peak. The sCnx was further purified and characterised. This showed that the protein had been cleaved after residue 472 (between Gln and Met), thus liberating it from the transmembrane and cytoplasmic parts of Cnx. The extraction and initial purification steps were carried out in the presence of protease inhibitors, thus ruling out that the cleavage was an artefact of the isolation procedure. This indicates that sCnx may have a physiological chaperone function similar to that of Crt.

AB - Calreticulin (Crt) and calnexin (Cnx) are homologous endoplasmic reticulum (ER) chaperones involved in protein folding and quality control. Crt is a soluble ER luminal Mr 46 kDa protein and Cnx is a Mr 67kDa ER membrane protein. During purification of Crt from human placenta a soluble form of Cnx (sCnx) was consistently identified in a separate ion exchange chromatography peak. The sCnx was further purified and characterised. This showed that the protein had been cleaved after residue 472 (between Gln and Met), thus liberating it from the transmembrane and cytoplasmic parts of Cnx. The extraction and initial purification steps were carried out in the presence of protease inhibitors, thus ruling out that the cleavage was an artefact of the isolation procedure. This indicates that sCnx may have a physiological chaperone function similar to that of Crt.

U2 - 10.1016/j.pep.2013.09.006

DO - 10.1016/j.pep.2013.09.006

M3 - Journal article

C2 - 24056258

VL - 92

SP - 105

EP - 111

JO - Protein Expression and Purification

JF - Protein Expression and Purification

SN - 1046-5928

IS - 1

ER -