Aza-Crown-Capped Porphyrin Models of Myoglobin: Studies of the Steric Interactions of Gas Binding - Université de Rennes Access content directly
Journal Articles Journal of the American Chemical Society Year : 1997

Aza-Crown-Capped Porphyrin Models of Myoglobin: Studies of the Steric Interactions of Gas Binding

Abstract

A series of myoglobin active site analogues (1-6) has been synthesized and characterized. These synthetic models differ in their cavity dimensions, and have been designed to demonstrate the effects of steric factors on O2 and CO binding affinities. Quantitative gas titrations were employed to measure these affinities, yielding M values that are strikingly lower than those reported for hemoglobin and myoglobin. The 1,4,7-triazacyclononane-capped porphyrin 1 has about 1200 times the CO affinity but only about 10 times the O2 affinity of the cyclam-capped porphyrin 2, suggesting a more open gas binding cavity for 1. The cavity dimensions and conformation of 2 were determined by single-crystal X-ray structural analysis of the Zn analogue 7. This paper unequivocally demonstrates that steric effects can control the ratio of O2/CO binding constants.

Dates and versions

hal-01469649 , version 1 (16-02-2017)

Identifiers

Cite

James P. Collman, Paul C. Herrmann, Lei Fu, Todd Eberscpacher, Mike Eubanks, et al.. Aza-Crown-Capped Porphyrin Models of Myoglobin: Studies of the Steric Interactions of Gas Binding. Journal of the American Chemical Society, 1997, 119 (15), pp.3481-3489. ⟨10.1021/ja963945i⟩. ⟨hal-01469649⟩
62 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More