Abstract
1. The enzymic removal of sialic acid residues from the glycoproteins of the human erythrocyte decreases the solubilization of membrane glycoprotein by Triton X-100. 2. The solubilization of asialoglycoprotein by Triton X-100 may be restored by the addition of borate. 3. Use of this non-ionic detergent in the presence of borate, as a general procedure for the mild solubilization of membrane glycoproteins deficient in sialic acid residues, is discussed.