March 1, 1985Proceedings of the National Academy of Sciences168 citationsOpen Access
View Full PaperThe NADPH binding site on beef liver catalase.
Key Points
Key points are not available for this paper at this time.
Abstract
Beef liver and human erythrocyte catalases (EC 1.11.1.6) bind NADP tenaciously Kirkman, H. N. & Gaetani, G. F. (1984) Proc. Natl. Acad. Sci. USA 81, 4343-4348. The position of NADP on beef liver catalase corresponds to the carboxyl-terminal polypeptide hinge in Penicillium vitale fungal catalase, which connects the common catalase structure to the additional flavodoxin-like domain. In contrast to nearly all other known structures of protein-bound NADP, NAD, and FAD, the NADP molecule of beef liver catalase is folded into a right-handed helix and bound, in part, in the vicinity of the carboxyl end of two alpha-helices. A water molecule (W7) occupies a pseudosubstrate site close to the C4 position of the nicotinamide and is hydrogen bonded to His-304. Although the NADP and heme groups approach each other to within 13.7 A, there is no direct interaction. The function of the NADP remains a mystery.