Gas-liquid chromatographic determination of sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate residues on soybeans and foliage, soil, milk, and liver.

Residues of sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate and its free acid are determined by treating a sample extract with diazomethane to convert the residues to methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate. This compound is purified by chromatography on Florisil and measured by electron capture gas-liquid chromatography. The method has been used on soybeans, soybean foliage, soil, milk, and liver.

Bimolecular (black) lipid membranes: study of lipid-protein interactions.

An experimental method has been devised for the study of the inter-action of bimolecular (black) lipid membrane and protein in which 8-anilino-1-naphthalenesulfonic acid is used as a fluorescent probe. The presence of phospho-lipid in the membrane is necessary for the enhanced fluorescence.

A comparison of the effects of ultraviolet and ionizing radiations on trypsin activity and on its constituent amino acids.

Photons of 254nm. u.v.

Photochemical yields in ribonuclease and oxidized glutathione irradiated at different wavelengths in the ultraviolet.

The quantum yields for the disruption of various amino acids in glutathione and ribonuclease by 229, 254, 265, and 280 nm UV photons have been determined. The results of the measurements on the destruction of tyrosine and histidine and the loss of enzymic function in RNAse and the disruption of cystine in both compounds lead to the following conclusions: (a) The photodestruction of some and perhaps many constituent amino acid residues does not cause RNAse inactivation. (b) Contrary to the basic premise of proposals made by other authors, the photochemical yields of constituent residues in a protein are not the same as that for the same amino acids in solution alone-the difference is a function of the exciting wavelength.