CHARACTERIZATION OF LANGMUIR-BLODGETT-FILMS OF RHODOPSIN - THERMAL-STABILITY STUDIES

Two-dimensional close packing of purified bovine rhodopsin, made by the Langmuir-Blodgett technique, was characterized by small angle x-ray scattering and nanogravimetric measurements. The area occupied by a molecule of rhodopsin in the film was similar to 1100 Angstrom(2) and the periodicity of the layers resulted in 59 Angstrom. The circular dichroism measurements showed that bleached rhodopsin in Langmuir-Blodgett film had high thermal stability, in fact, reaching a temperature of 150 degrees C without a loss of the secondary structure, Moreover, when the film was made up in the dark, rhodopsin maintained its stability up to at least 200 degrees C and its characteristic absorbance peak at 500 nm up to about 90 degrees C.