Sorbose: A ketose sugar that is commonly used in the commercial synthesis of ASCORBIC ACID.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.Axonal Transport: The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)Ion Transport: The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.Membrane Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.Protein Transport: The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Monosaccharide Transport Proteins: A large group of membrane transport proteins that shuttle MONOSACCHARIDES across CELL MEMBRANES.Kinetics: The rate dynamics in chemical or physical systems.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Electron Transport: The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Transport Vesicles: Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Biological Products: Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.Anion Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of negatively charged molecules (anions) across a biological membrane.Cation Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.Glucose: A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Golgi Apparatus: A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Vesicular Transport Proteins: A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Amino Acid Transport Systems: Cellular proteins and protein complexes that transport amino acids across biological membranes.Biological Assay: A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Biological Therapy: Treatment of diseases with biological materials or biological response modifiers, such as the use of GENES; CELLS; TISSUES; organs; SERUM; VACCINES; and humoral agents.