Mutations in the myostatin precursor protein inhibit covalent dimerisation and increase aggregation during refolding. A. (i) Reducing (R) versus non-reducing (NR) SDS-PAGE (12%) analysis of dimer (D) and monomer (M) ratios for purified precursor protein dimers after gel filtration chromatography; (ii) Quantitative densitometry analysis of relative proportions of monomer and dimer for each protein. Percentages are calculated relative to the fully reduced monomer. Statistical significance was calculated using a paired Student's t-test where * is P < 0.0001 for monomers relative to the WT monomer and **<0.0001 for dimers relative to the WT dimer. B. Gel filtration chromatography of (i) C313Y-MstnPP; (i) C313A-MstnPP and (iii) C374A-MstnPP. Peaks are labeled as follows: A1, void volume aggregates; A2, lower molecular weight aggregates; D, dimer.