Effect of cell age on the quenching of erythrocyte membrane protein fluorescence.

The accessibility of membrane protein tyrosyl and tryptophanyl residues for fluorescence quenchers (acrylamide and iodide) was compared in membranes isolated from various age fractions of bovine erythrocytes. An increase in the quenching efficiency of membrane protein fluorescence was found with advancing erythrocyte age, as demonstrated by elevated values of the Stern-Volmer constant. These results provide evidence for a progressive change in membrane protein organization during erythrocyte aging, enhancing the availability of membrane proteins for interactions with external factors.