Proton NMR study of the mechanism of the heme-apoprotein reaction for myoglobin. Jue, T.; Krishnamoorthi, R.; La Mar, Gerd N. Dep. Chem., Univ. California, Davis, CA, USA. J. Am. Chem. Soc. (1983), 105(17), 5701-3.

Abstract

1H NMR spectroscopy is used to study the mechanism by which apomyoglobin interacts with heme to form the holoprotein. In contrast to classic optical studies of the refolding process by which the native state is reached in a millisecond time scale, the present results indicate the presence of an intermediate which converts the holoprotein with a half-life of 5 x 104 s at physiol. pH. Moreover, .apprx.10% of the intermediate is present at equil., indicating that the native protein is itself heterogeneous. The slow rate of conversion suggests that in the native protein either a conformational uniqueness is controlled by enzyme mediation in the biosynthesis pathway or heterogeneous heme order is prevalent in vivo.