Rubisco enables net carbon fixation through the carboxylation of RuBP during photosynthesis. Its complex biochemistry and the catalytic diversity found amongst different plants makes characterization of Rubisco properties useful for investigations aimed at improving photosynthetic performance. This chapter reports methods for rapid extraction of soluble proteins to examine Rubisco catalytic properties, and for large scale purification of Rubisco from leaves to measure the specificity of the enzyme towards its gaseous substrates.