A novel 53-kDa polypeptide from chicken embryo
| Autor: | Richard A. Berg, J A Bassuk |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
inorganic chemicals
chemistry.chemical_classification biology Edman degradation Ion chromatography Cell Biology Biochemistry Molecular biology Epitope nervous system diseases Amino acid body regions N-terminus chemistry.chemical_compound Enzyme chemistry biology.protein Cyanogen bromide Antibody Molecular Biology |
| Zdroj: | Journal of Biological Chemistry. 266:23732-23738 |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/s0021-9258(18)54344-1 |
| Popis: | We have isolated from chicken embryos a novel 53-kDa protein possessing properties which are similar, but not identical to the 55-kDa PDI polypeptide from chicken embryos. The novel 53-kDa polypeptide copurifies with PDI, but is separated by ion-exchange chromatography. The novel 53-kDa polypeptide cross-reacts strongly with antibodies specific for bovine PDI and cross-reacts to varying degrees with six different preparations of antibodies specific for chicken PDI which is identical to the beta-subunit of chicken prolyl 4-hydroxylase. Anti-bovine PDI immunoglobulins selected by the purified 53-kDa polypeptide react with bovine PDI but not with the beta-subunit of prolyl 4-hydroxylase, suggesting that the 53-kDa polypeptide shares epitopes with bovine PDI but not with the chicken prolyl 4-hydroxylase beta-subunit. Amino acid compositional analysis of the purified polypeptide yielded unique data when compared to PDI and other PDI-like polypeptides. Edman degradation from the N terminus of the 53-kDa polypeptide yields a sequence very different from the N terminus of PDI. This sequence is unique when compared to all entries in available databases. A 20-residue sequence of an internal cyanogen bromide fragment of the 53-kDa polypeptide gives a nearly identical match with human beta-endorphin. The 53-kDa polypeptide is capable of cleaving the disulphides of insulin under conditions where PDI is active. The periodic acid-Schiff assay failed to detect bound carbohydrate. These observations support evidence for a family of PDI-like proteins in chicken embryo and suggest that PDI activity is not confined to only one protein. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|