Soluble Protein Assay to Quantify Soluble Protein Content in Plant Tissues

Abstract

Source: Deans, C. A. et al. Quantifying Plant Soluble Protein and Digestible Carbohydrate Content, Using Corn (Zea mays) As an Exemplar. J. Vis. Exp. (2018)

This video describes a colorimetric method to quantify the soluble protein content in plant tissues. The method uses Coomassie Brilliant Blue G-250 dye, which interacts with the soluble protein to form a blue-colored stable protein-dye complex, proportional to the soluble protein content in the tissue.

Protocol

1. Plant Collection and Processing

1. Collect and process plant samples
   1. After collecting plant samples, flash-freeze samples by dipping plant material into liquid nitrogen with forceps and store at -80 °C. If the plant samples collected are too large to flash-freeze, quickly cool the samples using dry ice and transfer to a -80 °C freezer as soon as possible. The macronutrient content of plant material can change after tissues are separated from the plant, so it is important to freeze plant samples as soon as possible after collection.
      CAUTION: Liquid nitrogen can cause severe frostbite when in contact with skin. ....

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Microplate reader (spectrophotometer)	Bio-Rad	Model 680 XR
Bio-Rad Protein Assay Dye Reagent concentrate	Bio-Rad	#5000006	450mL