An Improved Method of Preparing Haptoglobin Polypeptide Chains Using Guanidine Hydrochloride

An improved method is described to prepare haptoglobin polypeptide chains in high yield and purity. Reduction and alkylation in the presence or absence of guanidine were followed in both cases by fractionation on Sephadex G-200 in guanidine solutions at neutral pH. Extensive reduction in the presence of guanidine resulted in denatured chains suitable for structural study whereas milder reduction in the absence of guanidine yielded β chains capable of binding hemoglobin. Some physical, chemical, binding, and immunological studies on the isolated chains are described. The β chains of the common types of haptoglobin showed similarity in all these properties.