|MadSci Network: Biochemistry|
Hi, Bovine catalase does not absolutely require NADP for function. It is thought by some researchers that the role of NADP may be to help protect the enzyme against its very reactive substrate (H2O2), it is also known that the NADPH site can be involved in binding of cognate mRNA which regulates the level of catalase protein synthesis via sequestration of the messenger - this is a regulatory mechanism designed to sense oxidative state of the system in general. There are many types of catalases and peroxidases in Nature, some with prosthetic factors like NADP and some without. It is not really easy to assign differences in catalytic activity to something as complex as nucleotide binding, especially when the system is designed for intricate and delicate control of complicated intracellular processes. If I were you, I would read further on the relationship between catalase and metabolic processes (including alcohol metabolism!) and try to summarize the complex regulatory mechanism involved in catlase mRNA complexation. Good luck, feel free to ask further questions. A.G.E. Putnam,C.D., Arvai,A.S., Bourne,Y., Tainer,J.A., Active and inhibited human catalase structures: ligand and NADPH binding and catalytic mechanism. (2000) J. Mol. Biol. 296:295-309 Eventoff, William. (1976) Crystalline Bovine Liver Catalase. J. Mol. Biol. 103, 799-801. Fita, et al. (1985) The active center of catalase. J. Mol. Biol. 185, 21- 37. Fita, et al. (1986) The refined structure of beef liver catalase. Acta Cryst. B42, 497-515. Jouve, et al. (1991) Crystallization and crystal packing of Proteus mirabilis PR catalase. J. Mol. Biol. 221, 1075-77. Mathur, et al. (1981) Structure of beef liver catalase. J. Mol. Biol. 152, 465-99. Melik-Adamyan, et al. (1986) Comparison of beef liver and Penicillium vitale catalases. J. Mol. Biol. 188, 63-72. Reid, et al. (1981) Structure and heme environment of beef liver catalase at 2.5 A resolution. Proc. Natl. Acad. Sci. USA 78, 4767-71. Vainshtein, et al. (1981) Three-dimensional structure of the enzyme catalase. Nature 293, 411-12. Vainshtein, et al. (1986) Three-dimensional structure of catalase from Penicillium vitale at 2.0 A resolution. J. Mol. Biol. 188, 49-61.
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