In order to obtain information on the stability of chlorophyll-protein complex in the chloroplast of plant tissues, the effect of heat, acid, light and transition metals (Fe
2+ and Fe
3+) on the chlorophyll of model system with chlorophyll a and egg-albumin was studied.
1. Chlorophyll which is not combined with protein is easily decomposed by heat (60°C) and acid (citric acid-HCl buffer solution, pH 5.0). Furthermore, it is *remarkably decomposed by light. While, the chlorophyll of chlorophyll-protein system is relatively stable as compared with chlorophyll uncombined with protein.
2. Chlorophyll which is not combined with protein is easily decomposed by the transition metals Fe
2+ (10
-3M) and Fe
3+ (10
-3M). Especially, it is notably decomposed by Fe
3+. While, the chlorophyll of chlorophyll-protein system is remarkably stable against transition metals Fe
2+ and Fe
3+.
3. On the basis of the above results, the author suggests that the chlorophyll-protein complex in the chloroplast is relatively stable against heat, acid and transition metals.
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