Further evidence on the protein complexes of some hyaluronic acids

Abstract

Digestion with papain in conjunction with the measurement of non-Newtonian viscosity was used as a test for the presence of protein in the form of a complex with hyaluronic acid derived from several sources. This test shows that hyaluronic acid exists as a complex with protein in human synovial fluid and human umbilical cord, as well as in ox synovial fluid. Hyaluronic acid from ox vitreous humor shows no non-Newtonian viscosity and this test therefore provides no evidence that it contains protein. Papain has no detectable action on bacterial hyaluronic acid free from protein. The character of the mucin clot is well correlated with the non-Newtonian viscosity; hyaluronic acid-protein complexes give normal (group I) clots, but abnormal (group II or III) clots after digestion with papain. Hyaluronic acid from vitreous humor gives an abnormal clot. Plasmin has effects similar to those of papain, both on non-Newtonian viscosity and on the character of the mucin clot. Precipitation of hyaluronic acid from ox synovial fluid with cetylpyridinium chloride gives a protein complex indistinguishable from that prepared by filtration and present in the native fluid. The bearing of these results on the state of hyaluronic acid in pathological conditions is discussed.