[Regularities of formation of chlorophyll-human serum albumin functionally active complexes in the aqueous medium].
In the system with constant content of the chlorophyll a and increasing amounts of human serum albumin, dependence of pigment incorporation into the complex upon interaction of its aqueous associates with protein solutions was studied by applying the gel filtration on Sephadex G-75 and by measuring light scattering and rate of sensitized photoreduction of the methyl red by ascorbic-acid. The curves were obtained after extraction of the chlorophyll by acetone from dry pigment-protein films formed after desiccation of the aqueous systems. Sigmoid character of the above dependences, their linearization in Hill's coordinates and the value of cooperativity coefficient close to 2 testifies in favour of the cooperative character of the complex formation, two pigment molecules reacting with a single protein molecule. Measurement of adsorption isotherms and their treatment with use of the Brunauer-Emmett-Teller theory of polymolecular adsorption make it possible to evaluate the maximum molar ratio of the pigment to the protein in the complex (close to 2). The pigment-pigment interaction suggests that the chlorophyll molecules adsorbed on the protein are in the state of loosely packed dimers. Deaggregation of aqueus pigment associates by the protein in the course of complex formation results in a considerable increase of the protosensitizing chlorophyll activity.
D001665:Binding Sites; D002734:Chlorophyll; D006801:Humans; D007700:Kinetics; D008027:Light; D008433:Mathematics; D011485:Protein Binding; D012542:Scattering, Radiation; D012709:Serum Albumin; D013696:Temperature; D013816:Thermodynamics
D012709:Serum Albumin; D002734:Chlorophyll
Eakonomernosti obrazovaniia funktsional'no-aktivnykh kompleksov khlorofilla s syvorotochnym al'buminom cheloveka v vodnoĭ srede