The samples were diluted with 10 mM ammonium carbonate buffer pH 7.4 to a concentration of 0.5 mg/mL (protein component mass) and were mixed 4+1 (v/v) with a sample buffer containing 312.5 mM TRIS, 50% (v/v) glycerol, and 0.5 g/l bromophenol blue, pH 6.8. Volumes of 5 µL were loaded onto native 8% polyacrylamide gels with 3.75% stacking gels, which were prepared in a Bio-Rad multicasting chamber using a standard gel casting protocol (consecutive combination of TRIS buffer, acrylamide solution, APS, and TEMED). Electrophoresis was performed for 135 min at 80 V using a Bio-Rad Mini-PROTEAN™ Tetra Cell electrophoresis system with a 25 mM TRIS, 192 mM glycine running buffer. Afterwards, the gels were stained with Coomassie®-staining solution. A calibration curve (2nd order polynomial fit) was generated from the size of each NativeMark™ protein standard (size according to Holzer et al (2017)23 (link)) and the respective distance from the bromophenol blue band. The analyte size was then calculated from the band distance accordingly.