Two conformational forms of human γG globulin have been distinguished by their differing behavior on incubation with papain in the absence of cysteine. A 'papain-resistant' form is separated intact from the products of digestion of the predominant 'papain-sensitive' form by gel-filtration on Sephadex G-100. Structural alterations induced in the 'papain-resistant' form by pre-treatment with cysteine have been shown to render it susceptible to subsequent proteolysis by the enzyme in the absence of further reducing agent. Myeloma γG globulins with characteristics resembling each of these two forms of normal γG globulin have also been studied. The results thus obtained, by analytical gel-filtration of papain digests, are discussed in relation to methods applied by other investigators for the differentiation of γ G globulin molecules of varying susceptibility to papain proteolysis.
|Publication status||Published - Mar 1967|
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