Ethanol Extraction Requirement for Purification of Protein Labeled with [3H]Leucine in Aquatic Bacterial Production Studies

The trichloroacetic acid (TCA)-insoluble fraction of water column bacteria labeled with ³H]leucine contained an ethanol-soluble fraction accounting for up to 44% of the label. A component of the ethanol-soluble fraction is ³H]leucine. Labeled-protein purification requires an ethanol wash step. Cold TCA can replace hot TCA for precipitation of labeled proteins.