Protein-Sulfhydryl Groups In Cell Control Mechanisms

To the Editor:— Sensitivity tests on hundreds of animal and human cancers have shown greater attack on cancers than normal tissues by selected drugs reacting with sulfhydryl (SH) groups, drugs termed SH inhibitors.¹⁻³Nature herself appears to control cell division by regulating SH groups.⁴ Cancer probably devolves to derangement of regulatory mechanisms for mitosis about which little is known except that very large numbers of chemical reactions must occur simultaneously or in interrelated sequence for mitosis to occur. Either huge numbers of separate regulatory mechanisms and separate chemical receptors for regulators may be involved, or a single common chemical denominator may be crucial in turning on and off the host of reactions. Because of its inherent simplicity, the latter hypothesis may be the more probable.³,⁴ Protein-SH groups play essential roles at multiple levels of cell control processes. To earlier data¹⁻⁵on the importance of protein-SH groups