| Summary: | 碩士 === 中興大學 === 動物科學系所 === 95 === The purpose of this study was to extract insoluble elastin from pig aorta prepared from double lyophilized method or liquid nitrogen plus lyophilized method. The insoluble elastin was hydrolyzed by different E/S ratios (1:1, 1:2, 1:3, 1:4), substrate concentrations (5, 10, 15 mg/mL) and hydrolysis time (12, 24, 48 hr) to obtain soluble elastin. The characteristics of soluble elastin were evaluated by SDS-PAGE, ultraviolet absorption spectra, yield, protein concentration, thermal stability, amino acid composition and microstructure observation.
The results showed that the characteristics of insoluble elastin prepared from double lyophilized method or liquid nitrogen plus lyophilized method were similar. Two insoluble elastins were yellow in appearance. Amino acid composition of insoluble elastins from the two methods were composed of non-polar amino acids such as glycine, alanine, valine and proline. A flattened sheet with fibers was exhibited when insoluble elastin was observed by SEM. In thermal stability, insoluble elastin had lower thermal transition temperature (Tp) than that of raw material (pig aorta) (p<0.05).
The characteristics of soluble elastin prepared from insoluble elastin by different hydrolysis conditions such as E/S ratio, substrate concentration and hydrolysis time were similar. In appearance, all soluble elastins were slightly clear powder. No band was found when soluble elastin was performed by SDS-PAGE. In ultraviolet absorption spectra, all soluble elastins had a absorption peak at 274 or 275nm. It could be a distinctive amino acid- desmosine or isodesmosine, which was only presented in elastin. In the result of yield, E/S ratio was 1:2 and hydrolysis time for 48hr had the highest yield (double lyophilized method was 83.58% and liquid nitrogen plus lyophilized method was 87.95%). In the result of thermal stability, soluble elastin had lower thermal transition temperature (To and Tp) than insoluble elastin (p<0.05). In the result of amino acid composition, soluble elastins were composed of non-polar amino acids such as glycine, alanine, valine and proline. In the result of microstructure observation, soluble elastin had the sheet structure.
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