Amino acid incorporation capacity of cell-free systems from embryonic axes of Phaseolus coccineus

Cell-free protein synthesising systems, containing cytoplasmic ribosomes and 105,000 g supernatant were prepared from ungerminated (0 hr) axes and 12 hr germinated axes of white runner bean (Phaseolus coccineus L.)- The 12 hr system incorporate at least five times more ¹⁴C-leucine than the 0 hr system. Addition of poly-U enhances the incorporation of ¹⁴C-phenylalanine of both the systems. Combination of 12 hr ribosomes with 0 hr supernatant and vice versa shows that the major defect in the 0 hr system is located in the 0 hr ribosomes rather than in the 0 hr supernatant. Futhermore, the poor performance of the 0 hr ribesomal fraction is not due to a loosely bound inhibitor since the addition of 0 hr ribosomes to an active 12 hr ribosomal fraction does not hinder its activity.