Purification of 5‐Aminolaevulinate Synthase from Liver Mitochondria of Chick Embryo

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Abstract
5-Aminolevulinate synthase from chick-embryo liver mitochondria was, for the first time, purified to homogeneity in its native non-degraded form by molecular sieve chromatography, chromatofocusing and affinity chromatoraphy. The enzyme has a minimum MW of 68,000 as determined by sodium dodecylsulfate/polyacrylamide gel electrophoresis and a specific activity of 35,000 units/mg of protein. This result conflicts with the previous report of Whiting, and Granick (1976) that the chick embryo enzyme has a MW of 49,000. The purified form can be degraded proteolytically to a smaller form of MW around 50,000 while retaining full enzymatic activity. It seems evident, therefore, that the enzyme isolated by Whiting and Granick (1976) was degraded. Pulse-labeling studies and immunoprecipitation further established that the enzyme isolated by this new and rapid procedure has the same minimum MW as that which exists in vivo.