On Glutathione : a Reinvestigation. by Frederick Gowland Hopkins. with a Section in the Text by Leslie

In 1927 Hunter and Eagles (1) published an account of investigations which threw doubt upon the constitution of glutathione as apparently established by myself. At the time I was far from sharing these doubts, but I felt after the appearance of Hunter and Eagles’ paper that it was desirable I should reinvestigate the matter, and, if possible, arrive at a method by which the pure thiol compound could be separated with certainty. Meanwhile a paper published by Johnson and Voegtlin (2) seemed to offer evidence in favor of the original formula, and to judge from current publications various observers have prepared the substance for use without acquiring doubts as to its nature. Nevertheless an observation of my own, to be mentioned presently, concerning products obtained essentially on the original lines made it urgently necessary to reinvestigate the constitution of the substance as well as the method of preparation. The result of the study now to be described has been to show that Hunter and Eagles were right in doubting that the substance is a simple dipeptide of glutamic acid and cysteine though its constitution differs from their provisional suggestions concerning it. The grave discomfort involved in making an admission of previous error is mitigated by the circumstance that I am now able to describe a method, not without special interest in itself, which with ease and rapidity separates from yeast and from red blood corpuscles a pure crystalline thiol compound with a peptide or quasipeptide structure. In the case of yeast the yield is relatively large, sufficient to show that the compound is by far the most