A rapid, simple, and sensitive 125I-postlabeling technique has been developed to allow detection of DNA-protein cross-links induced by environmental contaminants and carcinogens. This method is based on specific incorporation of 125I into tyrosine residues associated with DNA. Cultured Chinese hamster ovary cells were exposed to various crosslinking agents, e.g., UV light, K2CrO4, or NiCl2. DNA...

4-Deuterioglutamic acid was prepared by incubation in DzO of ammonium mesaconate with an extract of Clostri&urn tetanomorphum. In these extracts, methylaspartase catalyzed the formation of threo-3-methyl-L-aspartate-3-D, which was then rearranged to glutamate by the cobamide coenzyme-dependent glutamate mutase. The monodeuteriosuccinate obtained by chloramine-T oxidation of the glutamate showed...

The kinetics of oxidation cyclopentanol, cyclohexanol and cyclooctanol using Chloramine T in NaOH has been studied in the micellar phase using sodium dodecyl sulphate in the temperature range 30°C to 50°C to correlate the oxidation rate with the ring size of the cyclic alcohols. The effect of alcohol concentration, concentration of oxidising agent, ionic strength and temperature on the oxidatio...

We have used two methods for the preparation of a highly homogeneous insulin with high specific activity. After iodination with chloramine T, the labeled peptides were retained on a disposable Sep Pak cartridge and subsequently eluted. The eluted labeled insulins were further purified by either DEAE cellulose or high performance liquid chromatography (HPLC) to separate A14-125I- from A19-125I-i...

The kinetic properties of the closing of Na channels were studied in frog skeletal muscle to obtain information about the dependence of channel closing on the past history of the channel. Channel closing was studied in normal and modified channels. Chloramine-T was used to modify the channels so that inactivation was virtually removed. A series of depolarizing prepulse potentials was used to ac...