Anomalous stability of insulin at very high pressure

Summary Insulin is unaffected by pressures of 48,000 b in the solid state at room temperature, as elucidated both by spectroscopic measurements and bioassay. Its compression curve is reversible. The presence of water does not alter this property. Of a number of other proteins investigated insulin appears to be unique with regard to its pressure stability. The relative rigidity of the molecule combined with its small size may account for some of these properties.Acknowlegments. I should like to thank Prof. Willard F. Libby of the Department of Chemistry and Institute of Geophysics of the University of California, Los Angeles, for his interest and support of this study.