E. W. Thompson

A phylogeny of higher plants based on the amino acid sequences of cytochrome c and its biological implications

Higher plant phylogenetic trees were constructed from the amino acid sequences of cytochrome c from fifteen plants using the ‘ancestral sequence’ and ‘flexible numerical’ methods. The validity of these methods is discussed and the results obtained are compared with existing phylogenies based mainly on morphological characters.

Isolation and purification of cytochrome c from some species of higher plants.

Abstract Cytochrome c was isolated and purified from dark-grown seedlings of mung bean, sunflower, sesame, castor oil and buckwheat. The major steps of the method employed were adsorption on Amberlite CG-50, concentration on Sephadex CM-50, molecular sieve chromatography on Bio-gel P-30 and Sephadex G-50, and ion-exchange chromatography on CM-52 Cellulose. Unlike previous methods for the purification of cytochrome c this method did not involve the use of organic solvents during the initial extraction, or fractional precipitation of the protein with ammonium sulphate. The Ampholine iso-electric focusing technique was also investigated as a possible method in the purification of cytochrome c from plant sources. The final yield of purified cytochrome c from the various species was in the range 0·2–0·45 mg/kg dry seeds.