Hydroxyproline and the Shrinkage Temperature of Collagen

Dr. B. J. Rigby and Dr. J. D. Spikes 1 have quoted a value of 8.3 per cent for the hydroxyproline content of fibrinoid tissue as being taken from a paper by Bowes, Elliott and Moss 2 . The figure given in this paper is in fact 7.6 for the hydroxyproline-nitrogen expressed as per cent of the total nitrogen of the gelatin solution obtained on autoclaving fibrinoid tissue. Assuming a total nitrogen content of 18 per cent, this corresponds to 12.8 per cent hydroxyproline on protein weight which, according to Fig. 1 of Rigby and Spikes, should give a T s of 60° or more. Their suggestion that rheumatic effects are the result of a structural breakdown due to temperature effects only is, therefore, not supported.