Bca protein assay kit for low concentrations

Plasma protein concentrations were determined using a BCA Protein Assay Kit for low concentrations according to manufacturer’s instructions (Abcam, Cambridge, UK). Absorption was measured at 562 nm using a FLUOstar Plate Reader (BMG Labtech, Bucks, UK). All samples and standard controls were measured in duplicate.

Isolated plastoglobules in sucrose fractions were purified and concentrated in TrE buffer (5 mM Tricine-KOH, pH 7.5, 0.2 mM EDTA, and 0.2 mM dithiothreitol) using disposable ultrafiltration devices (Vivaspin 500 Concentrators, Sartorius Stedim Biotech GmbH, Goettingen, Germany). First, 400 µL of deterged fractions were precipitated as described previously [78 (link)], with slight modification; obtained PG proteins were resuspended in 10 µL in TrE buffer, and the BCA protein assay kit for low concentrations (ab207002, Abcam, Cambridge, UK) was used to quantify the protein content. The assay was performed according to the manufacturer’s instructions. An equal volume of every sample was added to the BCA working reagents, and the reactions were incubated for 120 min at 37 °C. Absorbance was read at 562 nm on a NanoDrop 2000/2000c Spectrophotometer (Thermo Fisher Scientific Inc., Waltham, MA, USA). Protein concentrations were calculated using bovine serum albumin (BSA) standards and a four-parameter logistic curve using NanoDrop BCA PROTEIN software (v. 1.6, Thermo Fisher Scientific Inc., Waltham, MA, USA).