The effect of sulfhydryl reagents upon the activity of 40S ribosomal subunits.

p-Chloromercuribenzoate inhibited the poly (U)-dependent binding of the Phe-tRNA to the 40S ribosomal subunit but displayed no inhibitory effect on the binding of poly (U) to the ribosome. Other sulfhydryl reagents tested, like N-ethylmaleimide and iodoacetamide, did not affect the binding of Phe-tRNA to the small ribosomal subunit.