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Journal of Plant Sciences
  Year: 2007 | Volume: 2 | Issue: 4 | Page No.: 425-432
DOI: 10.3923/jps.2007.425.432
 
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Comparative Studies on Thermodynamic Activation Data Between Malted and unmalted African Finger Millet Seed(Eluesine coracana) β-Amylase

Ayodele O. Kolawole and Joshua O. Ajele

Abstract:
The effect of 4-days malting on the thermo-activation thermodynamic data of β-amylase from African finger millet (Eluesine coracana) seed was determined and compared with that of the β-amylase purified from unmalted seed. The results showed that the relative importance of enthalpic (ΔH!) and entropic activation between malted and unmalted was different. The activation energy for catalysis of unmalted Eluesine coracana β-amylase was 2.00 kcal mol1. The free energy change (ΔG!), enthalpy change (ΔH!) and entropy change (ΔS!) for activation at 50°C (optimum temperature) were 15.60 kcal mol1, 1.36 kcal mol1 and -45.60 e.u. (entropy unit), respectively. The activation energy for catalysis of malted Eluesine coracana β-amylase was 7.539 kcal mol1. The free energy change (ΔG!), enthalpy change (ΔH!) and entropy change (ΔS!) for activation at 50°C were 15.60 kcal mol1, 6.90 kcal mol1 and -24.96 e.u., respectively. The purified β-amylase from malted seed at 90°C had an half life of 5.87 min with free energy of inactivation of 22.928 kcal mol1, enthalpy 14.640 kcal mol1 and entropy -22.83 e.u. The results indicated that malted seed β-amylase reaction is enthalpy driven and unmalted seed β-amylase reaction is entropy driven to activation complex. The thermoactiavtion data both for malted and unmalted shows that the reaction is bisubstrate with a unimolecular rate determining step. The thermodynamic data of inactivation suggest that the enzyme is less stable at higher temperatures.
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How to cite this article:

Ayodele O. Kolawole and Joshua O. Ajele, 2007. Comparative Studies on Thermodynamic Activation Data Between Malted and unmalted African Finger Millet Seed(Eluesine coracana) β-Amylase. Journal of Plant Sciences, 2: 425-432.

DOI: 10.3923/jps.2007.425.432

URL: https://scialert.net/abstract/?doi=jps.2007.425.432

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