 Fractions I, II, III, and IV are coprecipitated at 40% ethanol, with pH of 5.4 to 7.0, and temperature −3 to −7 degrees C. Fraction V is then precipitated at pH 4.8 and −10 degrees C. The high yields are due to a combination of a simplified process, with lower losses due to coprecipitation, and use of filtration.Higher purities were also achieved at 98% because of the higher ethanol levels, but the yields were lowered with the high purity.More recent methods involve the use of chromatography.