The purpose of this investigation has been to identify commonplace, inexpensive substances that might be used to link radioisotopes to antibodies. It was found that a high molecular weight component of bovine skim milk binds bismuth ion and might be used as a carrier of short-lived bismuth isotopes in radioimmunotherapy applications. The bismuth-binding material may be complexed with Bi (as the Bi cation) and biotinylated using the reagent N-hydroxysuccinimido-D-biotin. Avidin on agarose columns sequestered 69% of the applied biotinylated product (S.D. 12%), whereas only 19% of the bismuth activity adhered to avidin columns that had been pre-blocked with D-biotin (S.D. 7%). Complexed with the short-lived alpha emitter Bi, the biotinylated product might be used in pre-targeting modes of radioimmunotherapy without modification. The bismuth-binding agent could be casein micelles, with Bi exchanging into Ca sites, but this has not been proven. ©1999 Oklahoma Academy of Science

We have studied the interaction of NBD-n-acylcholines, fluorescent analogs of acetylcholine with agonist action, with acetylcholine receptor and acetylcholine esterase (EC 3.1.1.7) from Electrophorus electricus. The rates of association of the fluorescent ligands with the two proteins are closely similar during the initial phase of binding, the second order rate constants being of the order of 2 × 108 M−1 s−1 at physiological salt conditions.

A characteristic red-violet chromophore which forms in the reaction of eupric ion with β-sulfhydryl- α-amino acids has been attributed by several authors to a mixed-valence Cu3L2 structure. We have isolated and examined the analogous chromophore of the chelating drug penicillamine (β,β-dimethyl-cysteine), finding instead a polymeric anion with a mixed valence Cu2L2 repeating unit. Direct evidence for a mixed valence polymer cooroborates earlier conclusions of Wilson and Martin [9]. Under oxygen-free conditions the anionic complex forms in essentially quantitative yield according to the following reaction: It has been established that this reaction is halide ion-dependent.