| dc.description.abstract | Transferrin is an 80K Dalton dimeric glycoprotein known primarily for its role as a transport protein for iron in mammalian systems. Transferrin (Tf) is also known to bind a number of other ligands under physiologic conditions, including zinc, cadmium, and manganese. Manganese is a vital component of many enzyme systems. Little is known about physiologic transport and uptake of manganese. Evidence has suggested a possible relationship to transferrin (3, 4, 11), and in this experiment, I have attempted to further elucidate the transferrin-manganese relationship. Several characteristics were examined. First, the spectrophotometric properties of the transferrin-manganese complex were studied. Also, the conditions under which complex formation progressed were examined. In particular, the presence of an oxidative agent for manganese, especially the oxidase ceruloplasmin (Cp), was measured as a factor in the rate of complex formation. The overall goal became to increase understanding about the mechanism by which manganese binds to Tf, as compared to iron-transferrin, so that the process of physiologic transport and uptake of manganese may be further understood. The complex was found to have a particularly characteristic peak at 415nm, with an extinction coefficient of 1200. The presence of bicarbonate was instrumental in the formation of the complex as was an oxidative component. Oxidative components greatly increased the rate at which the complex formed. Both peroxide and permanganate were able to hasten the reaction, both which having inherent problems in measuring the complex. Ceruloplasmin was able to catalyze the complex formation at physiologic levels. The oxidative nature of the complex formation was supported by EPR study. Also, Cp was blocked from effecting the complex by azide but not by catalase, intimating evidence that it is the oxidase core of ceruloplasmin which is essential in the complex formation, probably through the oxidation of manganese to the 3+ state. | en |
