Erythrocyte membrane peripheral and integral proteins have been isolated and purified, and the lateral diffusion of these proteins in a well-defined phospholipid bilayer matrix (dimyristoylphosphatidylcholine) has been studied by fluorescence photobleaching recovery measurements. Our own instrument for the recovery measurements is described and some data for lipid diffusions are compared with those previously reported by other investigators. The peripheral proteins (spectrin and band 4.1) diffuse rapidly on the lipid membrane in its fluid phase. The diffusion constant of approximately 5 x 10(-8) cm2 . s-1 (30 degrees C) was only a little smaller than that for lipid diffusion. The diffusion was greatly slowed down when the host lipid matrix became solid. The integral protein band 3 also diffuses rapidly in the fluid membrane. The diffusion constant of 1.6 x 10(-8) cm2 . s-1 (30 degrees C) was smaller than those for lipids and for the peripheral proteins. The lateral motion is compatible with diffusion of a cylinder with radius 3 nm in a two dimensional matrix with an inner viscosity of 2 poises and an inner thickness of 4 nm. The band 3 lateral motion was restricted by binding of the cytoskeletal component proteins (ankyrin, spectrin, actin, and band 4.1) to the reconstituted membranes. The diffusion constant decreased to half. The results provide a basis for the elucidation of transmembrane control mechanisms in more complex cellular systems.
A systematic study for the effect of axially coordinated monovalent anions on the electrode reactions of several manganese porphyrins in acetonitrile is presented. Potential shifts of the metal‐centered reduction with changes in counterion were related to the degree of Mn(III)‐counterion interaction. In the electrochemically induced ligand exchange, perchlorate anion replaces the other anions as axial ligand coordinated to Mn(III) at oxidation potential less than the first oxidation of manganese porphyrins. Formation constants for axial ligation of OH− are calculated. One‐electron oxidation of dihydroxide coordinated manganese porphyrins generate oxomanganese(IV) porphyrin complexes electrochemically. O=MnIVOEP(OH) is more thermodynamically stable than O=MnIVTPP(OH), while O=MnIVTpFPP(OH) cannot be generated electrochemically. In the presence of styrene or cyclohexene, the absorption spectra of oxomanganese(IV) porphyrins are changed to form manganese(III) porphyrins gradually, which indicates the oxygen atom transfer from oxomanganese(IV) porphyrins to the substrates.
In paperr 'ye propose a new (2-D) systolic-array digital filter using locally broadcast scheme that is the hybrid of a modijied reordering and another systolicThis architecture occlrpies locally broadcusl, lower quantization error and latency IIR digital filter, and N I x N 2 is the order of the IIR digital filter. We deduce the structure under the assumption of N I = N , = N , and then we pay attention to derive 2-D [IR digital filter architecture. For the sake of reducing the critical period, .we apply another systolic transformation as Ivithoi,t .yac,.ificing the of as we[[ as
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.