Interactions between astrocytes and blood vessels are essential for the for-mation and maintenance of the blood–neural barrier (BNB). Astrocyte-derived A-kinase anchor protein 12 (AKAP12) influences BNB formation,
but the mechanism of regulation of BNB functions by AKAP12 is not fully
Cell membranes act as barriers to most, but not all, molecules. The development of a cell membrane that could allow some materials to pass while constraining the movement of other molecules was a major step in the evolution of the cell. Cell membranes are differentially (or semi-) permeable barriers separating the inner cellular environment from the outer cellular (or external) environment.
Discovery of a new chemical entity that exerts pharmacological effects for
curing or treating diseases or relieving symptoms is only the first step in
the drug developmental process. In the developmental cycle of a new
drug, the delivery of a desired amount of a therapeutic agent to the target
at a specific time or duration is as important as its discovery. In order
to realize the optimal therapeutic outcomes, a delivery system should
be designed to achieve the optimal drug concentration at a predetermined
rate and at the desired location....
The conformational dynamics of NADH oxidase from
Thermus thermophiluswas modulated by the Hofmeister
series of anions (H2PO4
) in the concentration range 0–3M. Both cha-otropic and kosmotropic anions,at high concentration,
inhibit the enzyme by different mechanisms. Chaotropic
anions increase the apparent Michaelis constant and decre-ase the activation barrier of the reaction. Kosmotropic ani-ons have the opposite effect.
The prion-forming domain comprising residues 218–289 of the fungal prion
HET-s forms infectious amyloid fibrils at physiological pH. Because a
high-resolution molecular model for the structure of these fibrils exists, it
constitutes an attractive system with which to study the mechanism of amy-loid assembly.
Epithelial mucins are large complex cell surface and secreted glycoproteins produced by
mucosal epithelial cells. Mucins are a major component of the interface between the external
world and mucosal tissues, where they provide lubrication, hydration, and a biological
and physical barrier to potential toxins, particles, and pathogens. Mucins provide many
challenges to researchers due to their large size, complex biochemical nature, and the viscous
gels that they form when secreted.
The recent convergence of genetic and biochemical evidence on the activit-ies of lipoxygenase (LOX) enzymes has implicated the production of hep-oxilin derivatives (fatty acid epoxyalcohols) in the pathways leading to
formation of the water-impermeable barrier of the outer epidermis.