Purification and characterization of ribosomal proteins. 2. Purification of Drosophila ribosomal proteins. Isolation of proteins S8, S13, S14, S16, S19, S20/L24, S22/L26, S24, S25/S27, S26, S29, L4, L10/L11, L12, L13, L16, L18, L19, L27, 1, 7/8, 9, and 11

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Abstract
The proteins of D. melanogaster embryonic ribosomes were separated into 7 groups (A80 through G80) by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5. Three relatively acidic proteins, S14, S25/S27 and 7/8, were isolated from group A80 by ion-exchange chromatography on carboxymethylcellulose eluted with a linear gradient of LiCl at pH 4.2. Fractions containing the relatively basic proteins (groups B80 through G80) were further combined into 24 pools. The criterion for combination was the migration patterns in 1-dimensional polyacrylamide gels containing sodium dodecyl sulfate (NaDodSO4) of every 5th fraction from the carboxymethylcellulose column. Each pool contained between 1 and 12 major proteins. Proteins S8, S13, S16, S19, S20/L24, S22/L26, S24, S26, S29, L4, L10/L11, L12, L13, L16, L18, L19, L27, 1, 9 and 11 were isolated from selected pools by gel filtration through Sephadex G-100. The amount of each protein recovered from a starting amount of 1.8 g of total 80S proteins varied from 0.2 to 10.8 mg. Five proteins had no detectable contamination, and in each of the others the impurities were no greater than 90%. The amino acid composition of the individual purified proteins was determined. The MW of the proteins were estimated by polyacrylamide gel electrophoresis in NaDodSO4.