Isolation and Identification of Rubisco Extracted from Spinach Leaves

This paper evaluates a laboratory process for extracting, isolating, and identifying rubisco, an essential protein found in plant cells and an important catalyst during photosynthesis. Isolating rubisco from other proteins also found in plants requires a carefully planned series of laboratory procedures to separate the proteins on the basis of physical characteristics including solubility, electrical charge, and molecular size. In this study, ammonium sulfate precipitation was used to extract proteins from a sample of spinach leaves and to separate the proteins into two samples with different solubility characteristics. These samples were then subjected to ion exchange column chromatography using buffers with a range of salt concentrations to produce fractions with varying electrical charge characteristics. The resultant fractions were then analyzed via protein electrophoresis to determine the molecular weight of the isolated proteins, which were compared against the known molecular weight of rubisco. Fin...