The swelling of bovine ligamentum nuchae as a function of pH.

1. The swelling and solubilization of foetal and adult bovine ligament over a range of pH values has been investigated. 2. Maximum swelling occurs at pH2.7 and pH8.5 for both types of ligament. Abover pH13 complete solubilization occurs. 3. Considerably greater swelling and solubilization occurs with foetal ligament below pH12. 4. The presence of 2m-sodium chloride markedly suppresses both swelling and solubilization. Above 1n-sodium hydroxide actual dehydration occurs and little or no protein is extracted. 5. It is suggested that the intermolecular cross-links in a considerable proportion of foetal elastin are weak and that extraction with aqueous salt solution at pH8.5 would provide optimum conditions for extracting soluble proteins, including soluble elastin if this is present.