Commercially Purified Phycobiliproteins Can Be Substituted for Protein Purified from Spirulina to Save Lab Preparation Time for Undergraduate Thermodynamics and Protein Folding Experiments

Abstract

Phycobiliproteins purified from Spirulina dietary supplements have been used in undergraduate biochemistry and/or general chemistry laboratories to demonstrate protein folding and thermodynamic concepts such as equilibrium constants and Gibbs free energy. Preparing samples via purification of phycobiliproteins from Spirulina dietary supplements takes approximately 4 h. Instead of purifying phycobiliproteins from Spirulina to use in student laboratories, preparing samples from commercially purified phycobiliproteins, blue Spirulina powder, yields similar results while saving preparation time and avoiding the need for a centrifuge. Student data using phycobiliprotein purified from Spirulina or commercially purified phycobiliprotein provides nearly identical calculations of equilibrium constants and ΔG values at various urea concentrations, which give a ΔG of unfolding at 0 M urea near 10 kJ/mol regardless of the protein source. This suggests blue Spirulina powder’s use will save instructors’ lab preparation time and make this type of experiment more available for settings where the equipment for purifying phycobiliproteins from Spirulina is unavailable.