Studies on ethylene binding by cell-free preparations from cotyledons of Phaseolus vulgaris L. : I. Separation and characterisation.

The preparation is described of a cell-free system from developing cotyledons of Phaseolus vulgaris cv. Canadian Wonder which is capable of binding ethylene. The binding is saturable and the apparent dissociation constant for ethylene is 6.4·10(-10) M in solution. The binding site is associated with subcellular particles and treatment with Triton X-100 results in substantial solubilisation of the activity. The kinetics of association and dissociation of the ligand and the binding site are described. The system is heat labile and binding activity is diminished by treatment with some proteolytic enzymes.