Isolation and Characterization of Epidermal Ribosomes

The conditions required for isolation of ribosomal particles from guinea-pig epidermis and hair-root cells have been studied. Density-gradient patterns of the ribosomes following isolation from either tissue under a wide variety of conditions are essentially the same. Monomeric ribosomes are the predominant species isolable although polymeric ribosomes and subunits can be identified. The density-gradient pattern is not related to runoff during preparation. Detergent extraction is required for maximal recovery of particles from epidermis or wax-epilated hair roots. Ribosomes can be obtained in relatively high yield from latex-epilated hair roots even without detergent.The yield of ribosomes from both epidermis and hair roots is greatest in buffers with potassium concentrations between 100 and 250 mM. Yield is decreased in buffers with magnesium concentrations above 5 mM. Activity in an in vitro amino acid-incorporating system is unaffected by potassium concentration and is highest at magnesium concentration of 3 mM. Activity of epidermal ribosomes is inhibited by the wax-epilation method while hair root-cell ribosomes are equally active following preparation with either latex or wax. The isolated ribosomal particles are unstable at 4°C