title: A spectroscopic technique for measuring slow rotational diffusion of macromolecules. 1: Preparation and properties of a triplet probe.
abstract: Slow rotational diffusion may be investigated by measuring the decay of dichroism of flash-induced transient absorption changes of suitable probes. The preparation of the covalent ""triplets" probe eosin isothiocyanate is described together with investigations of spectroscopic properties of eosin-protein conjugates. Triplet state lifetimes of air-equilibrated solutions of eosin-protein conjugates are in the order of 10 mus, demonstrating that the probe is protected from oxygen quenching by the protein. Experiments with the sucrase-isomaltase complex from small intestine show that its enzymatic activity is little affected by binding up to 2 mol of eosin/mol of protein.
mesh_terms: D000818:Animals; D004058:Diffusion; D004801:Eosine Yellowish-(YS) / Q000031:analogs & derivatives; D005452:Fluoresceins; D006026:Glycoside Hydrolases; D007421:Intestine, Small / Q000201:enzymology; D010047:Ovalbumin; D011485:Protein Binding; D011506:Proteins; D011817:Rabbits; D012399:Rotation; D012710:Serum Albumin, Bovine; D013053:Spectrophotometry; D013395:Sucrose; D013861:Thiocyanates
chemical_list: D005452:Fluoresceins; D011506:Proteins; D013861:Thiocyanates; D012710:Serum Albumin, Bovine; D013395:Sucrose; C012957:eosine-5-isothiocyanate; D010047:Ovalbumin; D006026:Glycoside Hydrolases; D004801:Eosine Yellowish-(YS)