Photoenzymes: A novel class biological catalysts
- Cornell Univ., Ithaca, NY (United States)
Sunlight is essential for sustaining life on earth. In addition to photosynthesis, photochemical reactions are involved in vision, in the biosynthesis of vitamin D, and in the control of plant development. Enzymes that require light energy represent photosynthesis in its simplest biological form. At this time, only two photoenzymes have been identified. In the first system, bacteria that have been killed by irradiation with ultraviolet light can be revitalized by exposure to visible light. This remarkable phenomenon, called photoreactivation, is mediated by the enzyme DNA photolyase and plays a crucial role in protecting bacteria from the lethal and mutagenic effects of the UV component of sunlight. In the second process, yellow, dark-grown plants become green when transferred to the light. This greening reaction, catalyzed by the enzyme protochlorphyllide reductase, is a key step both in the biosynthesis of chlorophyll and in the morphogenesis of the chloroplast. This Account will summarize the current state of mechanistic studies on these two systems.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 232340
- Journal Information:
- Accounts of Chemical Research, Vol. 27, Issue 12; Other Information: PBD: Dec 1994
- Country of Publication:
- United States
- Language:
- English
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