Isolation of glycophorin with deoxycholate

Area of Science:

• Biochemistry
• Cell Biology
• Membrane Protein Research

Background:

• Human erythrocyte glycophorin is a key membrane protein.
• Previous purification methods using lithium diiodosalicylate resulted in significant bound detergent, which was difficult to remove.
• The bound detergent imparted a reddish-brown color to the purified glycophorin.

Purpose of the Study:

• To develop an alternative purification procedure for human erythrocyte glycophorin.
• To obtain a purer glycophorin preparation with minimal residual detergent.
• To improve the yield and quality of purified glycophorin.

Main Methods:

• Substitution of sodium deoxycholate for lithium diiodosalicylate in the purification process.
• Removal of sodium deoxycholate by gel filtration.
• Quantification of bound detergent using molar ratios.

Main Results:

• The sodium deoxycholate procedure yielded 25-30 mg of glycophorin per gram of erythrocyte ghosts.
• Glycophorin purified by this method contained less than 1 mol of sodium deoxycholate per mol of glycophorin.
• The resulting glycophorin was colorless, unlike the product from the lithium diiodosalicylate method.

Conclusions:

• The sodium deoxycholate and gel filtration method is an effective alternative for purifying human erythrocyte glycophorin.
• This new procedure yields a significantly purer and visually improved glycophorin preparation.
• The improved purity is evidenced by the minimal residual detergent and colorless appearance.