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|Type:||Artigo de periódico|
|Title:||The thermal stability of a castor bean seed acid phosphatase|
|Abstract:||The effect of temperature on the activity and structural stability of an acid phosphatase (EC 22.214.171.124.) purified from castor bean (Ricinus communis L.) seeds have been examined. The enzyme showed high activity at 45degreesC using p-nitrophenylphosphate (p-NPP) as substrate. The activation energy for the catalyzed reaction was 55.2 kJ mol(-1) and the enzyme maintained 50% of its activity even after 30 min at 55degreesC. Thermal inactivation studies showed an influence of pH in the loss of enzymatic activity at 60degreesC. A noticeable protective effect from thermal inactivation was observed when the enzyme was preincubated, at 60degreesC, with the reaction products inorganic phosphate - P (10 mM) and p-nitrophenol - p-NP(10 mM). Denaturation studies showed a relatively high transition temperature (T-m) value of 75degreesC and an influence of the combination of Pi (10 mM) and p-NP (10 mM) was observed on the conformational behaviour of the macromolecule.|
|Editor:||Kluwer Academic Publ|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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