As a result, both lipids and the apoB protein of the LDL particle undergo oxidation. Hp acts by trapping the heme in the Hp-Hb complex, such that it can no longer oxidize LDL. The Inhibition of hemeinduced ELR510444 oxidation even holds true in the case of the less effective form, Hp 2-2, and the vulnerable form of LDL, dLDL. These results clearly show that the efficiency of Hp in inhibition of Hb oxidative activity stems from preventing sensitive targets from associating with loosely-bound hemin. The specific protection afforded to Hb by Hp fits in well with our knowledge of the dissociation of Hb into ab dimers at low concentrations occurring in vivo. Hp prevents the escape of the loosely-bound hemin since it masks the surface of the ab dimer when it binds, covering a large part of the Hb interface. The current study indicates that CO provides some protection against oxidation of LDL by Hb, but this protection is much less efficient than that of Hp. The prominent difference between the two mechanisms by which Hb and Mb act, relates to the fact that heme transfer from Mb is negligible in comparison to Hb. Differences in mechanisms of the two proteins are especially prominent when observing the kinetics of LDL oxidation and its arrest by CO. LDL is oxidized by ferric-Mb at a constant rate, ALK-IN-1 appropriate for enzymatic function. This differs completely from the multistage rate of Hb-induced LDL oxidation. Despite a common physiological function, Hb and Mb differ in the mechanism by which they evoke oxidation. Hb oxidative activity results fundamentally from a weakening of the trivalent heme-globin bond. As discussed earlier, ferric-Hb redox activity is manifested by the presence of components that bind hemin strongly, such as LDL. Thus, only a high�Caffinity globin�Cbinding protein, such as Hp, can efficiently trap hemin. On the other hand, as suggested in the past and indicated in the current study, Mb��s oxidative power stems from a protein-bound ferric heme whose activity is peroxidase-like: namely, fully dependent on heme iron redox capability.