Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present experiments, selective quenching by trinitrophenyl groups as well as steady-state fluorescence polarization and differential polarized phase fluorescence techniques, using three different lipid soluble fluorophores, were used to directly examine the fluidity of the exofacial and cytofacial leaflets of rat small intestinal brush-border membranes. These studies revealed that the fluidity of the exofacial hemileaflet was greater than the cytofacial hemileaflet. Differences in the distribution of phosphatidylcholine and phosphatidylethanolamine, as assessed by phospholipase A2 treatment and trinitrophenylation of aminophospholipids, were, at least partially, responsible for the asymmetrical fluidity of the hemileaflets. Moreover, in vitro addition of benzyl alcohol (final concn 25 mM) preferentially fluidized the exofacial leaflet and concomitantly decreased leucine aminopeptidase activity but did not affect the activities of maltase, sucrase, alkaline phosphatase, or gamma-glutamyltranspeptidase. In vivo addition of the membrane-mobility agent 2-(2-methoxyethoxy)ethyl 8-(cis-2-n-octylcyclopropyl)octanate] (A2C) (final concn 7.5 microM) preferentially fluidized the cytofacial leaflet and increased Na(+)-gradient-dependent D-glucose transport but not Na(+)-gradient-dependent L-leucine transport.
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PMID:Characterization and modulation of rat small intestinal brush-border membrane transbilayer fluidity. 201 33

Rabbit intestinal glucoamylase-maltase was examined in detail with respect to its molecular weight, sedimentation, diffusion and viscosity. It is a large asymmetrical molecule, with a molecular weight of 750 000-760 000. Its appearance under the electron microscope supports the idea that it is a long string (62.0 nm) consisting of eight beads of diameter 6.0 nm each and a surface-to-surface interbead distance of approx. 2.0 nm. The shape of the enzyme derived from its hydrodynamic behaviour by using the string-of-spherical-beads model originally proposed by Kuhn [(1932) Z. Phys. Chem. Abt. A 161, 1-32] and later modified by Shulman [(1953) J. Am. Chem. Soc. 75, 5846-5852] fits moderately well with the electron-microscopic picture. The beads might represent about six subunits, and the absence of sulphur from the enzyme and the inability to dissociate the enzyme by conventional methods indicate the possibility of unusual covalent cross-linking between the subunits and between the beads.
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PMID:Studies on the size and shape of rabbit intestinal glucoamylase-maltase complex. 641 89