Dianthin 30 and 32 from Dianthus caryophyllus: two inhibitors of plant protein synthesis and their tissue distribution.

The ability of dianthin 30 and 32 to inhibit translation in reticulocyte lysates and wheat germ extracts has been studied. The dianthins, like the A chains of the toxins abrin and ricin, inhibited protein synthesis in reticulocyte lysates by inactivating the 60S ribosomal subunit. They also inhibited, at concentrations of 10 ng/ml, a protein-synthesizing system from wheat germ and inactivated isolated wheat germ ribosomes. The concentration of the dianthins in different tissues of the plant was determined by rocket immunoelectrophoresis and by the dianthin's ability to inhibit protein synthesis. Dianthin 32 was found only in the leaves and in growing shoots, while dianthin 30 was present throughout the plant. In the older parts of the plant, the dianthins constituted between 1 and 3% of the total extractable protein whereas much less was found in the younger parts.