The Cu,Zn superoxide dismutase isoenzymes of Xenopus laevis: purification, identification of a heterodimer and differential heat sensitivity
| Autor: | Mt Carri, Lilia Calabrese, Cr Capo, Giuseppe Rotilio, Me Schinina, Fabio Polticelli |
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| Jazyk: | angličtina |
| Rok vydání: | 1990 |
| Předmět: |
Hot Temperature
Dimer Molecular Sequence Data Biophysics Xenopus Protein dimer Biochemistry Sensitivity and Specificity Superoxide dismutase Xenopus laevis Superoxide Dismutase Animals Enzyme Activation Isoenzymes Chromatography Ion Exchange Amino Acid Sequence Isoelectric Focusing chemistry.chemical_compound superoxide dismutase PROTEIN PRIMARY STRUCTURE Settore BIO/10 Molecular Biology Thermostability chemistry.chemical_classification Chromatography biology Edman degradation Cell Biology biology.organism_classification Enzyme assay Ion Exchange Enzyme chemistry biology.protein |
| Popis: | The three Cu,Zn superoxide dismutase electromorphs of the amphibian Xenopus laevis were purified by an original procedure. N-terminal sequence analysis demonstrated that they are two different homodimers (AA and BB) and a hybrid heterodimer (AB), arising from the co-expression of duplicated genes. The three forms have the same pI, same enzyme activity and EPR spectra, but different heat-sensitivity, form BB being more resistant than form AA, with form AB showing intermediate sensitivity. Thermostability of BB and the control bovine enzyme was enhanced by a tenfold increase in protein concentration. It is suggested that the higher heat sensitivity of the AA isoenzyme is related to the presence of an extra Cys residue and to an easier dissociation of the protein dimer into monomers. |
| Databáze: | OpenAIRE |
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