Nonhemoglobin Proteins in Young and Old Red Blood Cells 1

Abstract

Summary

When young and old human red blood cells are lysed, more nonhemoglobin proteins are released from the young than from the old cells, reflecting the changed intracellular environment. Qualitatively, as judged by acrylamide-gel electrophoresis, there are no differences between the nonhemoglobin proteins from these two sources. It is shown for one enzyme (and known for many) that the enzyme activity associated with young cells is appreciably higher than that found in older cells. The lower quantity of nonhemoglobin proteins recovered from older cells may well be related to this phenomenon. Possibilities accounting for the smaller quantity of nonhemoglobin proteins recovered from older cells include protein catabolism in older cells or, more likely, an age-dependent interaction between nonhemoglobin proteins and the cell membrane.