Stabilization of glycogen phosphorylase b by reductive alkylation with aliphatic aldehydes
| Autor: | Jerry Hsueh-Ching Wang, Honor C. Ho, Morley A. Shatsky |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
Protein Denaturation
Hot Temperature Time Factors Alkylation Phosphorylases Kinetics Borohydrides Biochemistry Genetics and Molecular Biology (miscellaneous) Aldehyde Catalysis chemistry.chemical_compound Drug Stability Glyceraldehyde Centrifugation Density Gradient Organic chemistry Animals Thermal stability Amino Acids chemistry.chemical_classification Aldehydes Autoanalysis Muscles Acetaldehyde Cold Temperature Enzyme chemistry Electrophoresis Polyacrylamide Gel Rabbits Oxidation-Reduction Protein Binding |
| Zdroj: | Biochimica et biophysica acta. 303(2) |
| ISSN: | 0006-3002 |
| Popis: | Modification of glycogen phosphorylase b with NaBH4 and various homologous aliphatic aldehydes, from acetaldehyde to heptaldehyde, resulted in enzyme derivatives which exhibited enhanced resistance against heat and cold inactivations. Concentrations of the modifying aldehydes optimal for the enzyme stabilization were 0.5–0.75%. The modified phosphorylase b usually contained mixtures of enzyme derivatives with varying stability. The most stable derivatives in each of the different aldehyde derivatives were purified by heating of the modified enzymes at 50 °C for 3 h to denature the less stable derivatives. Comparison of the kinetics of heat and cold inactivation of the purified phosphorylase b derivatives indicated that the stability of the enzyme derivative was a function of the structure of the modifying aldehyde. As the aliphatic chain length increased from acetaldehyde to valeraldehyde, the stabilization of the enzyme against cold and heat denaturation increased. Further increase in the chain length of the modifying aldehyde, however, resulted in a slight decrease in the protein stability. The results suggested that the enzyme stabilization depended in part on the hydrophobic nature of the modifying aldehyde. The suggestion was supported by the observation that glyceraldehyde, a hydrophilic aldehyde, had little effect on the stability of phosphorylase b . Physical and catalytic properties of phosphorylase b derivatives other than the stability property, were similar to those of the native enzyme. These properties included specific enzyme activity, gel electrophoretic and sedimentation behaviours, and the crystallization in the presence of AMP and Mg2+. In addition, the modified enzyme could be converted to phosphorylase a which also exhibited higher thermal stability than native phosphorylase a . |
| Databáze: | OpenAIRE |
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