X-ray Inactivation of Lactate Dehydrogenase in Dilute Solution

Summary

X-irradiation of dilute solutions of LDH₅ in phosphate buffer induces, simultaneously with the loss of activity several changes of the protein structure which became obvious by measuring the u.v.-absorption spectrum, the amino-acid composition, and the titrable SH-groups. Furthermore the conformational changes cause the occurrence of four components different in molecular size which could be separated by gel-filtration. The results are compared with those obtained in similar experiments with ribonuclease.