A model to explain the osmotic pressure behavior of hemoglobin and serum albumin

Abstract

Previously published osmotic pressure data on hemoglobin and bovine serum albumin were used to determine the osmotically unresponsive solvent volume per unit dry mass of protein. A model is presented that accounts for the osmotic pressure of globular proteins based on a surface-associated osmotically unresponsive solvent volume. The model also accounts for changes in the osmotically unresponsive solvent volume owing to changes in pH, cosolute salt concentration, protein conformation, and protein aggregation.Key words: hemoglobin, serum albumin, osmotic pressure, water of hydration, salt, pH, model of protein structure.