Protein soluble aggregate assays
Soluble product aggregates were analyzed on a Waters UPLC system (Waters, Acquity H-Class PLUS) with UV detection at 280 nm, using an Acquity UPLC protein BEH SEC column (Waters, 125 Å, 1.7 μm, 4.6 mm×150 mm) and an Acquity UPLC protein BEH guard column (Waters, 4.6 mm × 30 mm). All samples were 0.2 μm filtered to remove potential large particles prior to applying a total mass of 50 μg protein to the SEC-UPLC system. The mobile phase (200 mM sodium phosphate, 150 mM sodium chloride, pH 6.8) was run at a flow rate of 0.4 mL/min. Results were analyzed using Waters Empower 3 chromatography data system software (Waters, version 3).