Glucokinase: A group of enzymes that catalyzes the conversion of ATP and D-glucose to ADP and D-glucose 6-phosphate. They are found in invertebrates and microorganisms, and are highly specific for glucose. (Enzyme Nomenclature, 1992) EC An enzyme that catalyzes the conversion of ATP and a D-hexose to ADP and a D-hexose 6-phosphate. D-Glucose, D-mannose, D-fructose, sorbitol, and D-glucosamine can act as acceptors; ITP and dATP can act as donors. The liver isoenzyme has sometimes been called glucokinase. (From Enzyme Nomenclature, 1992) EC 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.Mannoheptulose: A 7-carbon keto sugar having the mannose configuration.Dihydroxyacetone: A ketotriose compound. Its addition to blood preservation solutions results in better maintenance of 2,3-diphosphoglycerate levels during storage. It is readily phosphorylated to dihydroxyacetone phosphate by triokinase in erythrocytes. In combination with naphthoquinones it acts as a sunscreening agent.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Glucose Transporter Type 2: A glucose transport facilitator that is expressed primarily in PANCREATIC BETA CELLS; LIVER; and KIDNEYS. It may function as a GLUCOSE sensor to regulate INSULIN release and glucose HOMEOSTASIS.Islets of Langerhans: Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.Ninhydrin: 2,2-Dihydroxy-1H-indene-1,3-(2H)-dione. Reagent toxic to skin and mucus membranes. It is used in chemical assay for peptide bonds, i.e., protein determinations and has radiosensitizing properties.Insulin: A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).FructosephosphatesGlucose-6-Phosphate: An ester of glucose with phosphoric acid, made in the course of glucose metabolism by mammalian and other cells. It is a normal constituent of resting muscle and probably is in constant equilibrium with fructose-6-phosphate. (Stedman, 26th ed)Insulinoma: A benign tumor of the PANCREATIC BETA CELLS. Insulinoma secretes excess INSULIN resulting in HYPOGLYCEMIA.Liver Glycogen: Glycogen stored in the liver. (Dorland, 28th ed)Sorbitol: A polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications.Glycolysis: A metabolic process that converts GLUCOSE into two molecules of PYRUVIC ACID through a series of enzymatic reactions. Energy generated by this process is conserved in two molecules of ATP. Glycolysis is the universal catabolic pathway for glucose, free glucose, or glucose derived from complex CARBOHYDRATES, such as GLYCOGEN and STARCH.Fructose: A monosaccharide in sweet fruits and honey that is soluble in water, alcohol, or ether. It is used as a preservative and an intravenous infusion in parenteral feeding.Glucose-6-Phosphatase: An enzyme that catalyzes the conversion of D-glucose 6-phosphate and water to D-glucose and orthophosphate. EC, Islet Cell: A benign tumor of the pancreatic ISLET CELLS. Usually it involves the INSULIN-producing PANCREATIC BETA CELLS, as in INSULINOMA, resulting in HYPERINSULINISM.GlucosephosphatesRats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Pyruvate Kinase: ATP:pyruvate 2-O-phosphotransferase. A phosphotransferase that catalyzes reversibly the phosphorylation of pyruvate to phosphoenolpyruvate in the presence of ATP. It has four isozymes (L, R, M1, and M2). Deficiency of the enzyme results in hemolytic anemia. EC An allosteric enzyme that regulates glycolysis and gluconeogenesis by catalyzing the transfer of a phosphate group from ATP to fructose-6-phosphate to yield fructose-2,6-bisphosphate, an allosteric effector for the other 6-phosphofructokinase, PHOSPHOFRUCTOKINASE-1. Phosphofructokinase-2 is bifunctional: the dephosphorylated form is a kinase and the phosphorylated form is a phosphatase that breaks down fructose-2,6-bisphosphate to yield fructose-6-phosphate.Kinetics: The rate dynamics in chemical or physical systems.Phosphoenolpyruvate Carboxykinase (GTP): An enzyme of the lyase class that catalyzes the conversion of GTP and oxaloacetate to GDP, phosphoenolpyruvate, and carbon dioxide. This reaction is part of gluconeogenesis in the liver. The enzyme occurs in both the mitochondria and cytosol of mammalian liver. (From Dorland, 27th ed) EC Glucose: Glucose in blood.Glucagon: A 29-amino acid pancreatic peptide derived from proglucagon which is also the precursor of intestinal GLUCAGON-LIKE PEPTIDES. Glucagon is secreted by PANCREATIC ALPHA CELLS and plays an important role in regulation of BLOOD GLUCOSE concentration, ketone metabolism, and several other biochemical and physiological processes. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1511)Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.AlloxanDiabetes Mellitus, Type 2: A subclass of DIABETES MELLITUS that is not INSULIN-responsive or dependent (NIDDM). It is characterized initially by INSULIN RESISTANCE and HYPERINSULINEMIA; and eventually by GLUCOSE INTOLERANCE; HYPERGLYCEMIA; and overt diabetes. Type II diabetes mellitus is no longer considered a disease exclusively found in adults. Patients seldom develop KETOSIS but often exhibit OBESITY.HexosesEnzyme Activators: Compounds or factors that act on a specific enzyme to increase its activity.Hyperglycemia: Abnormally high BLOOD GLUCOSE level.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Adaptor Proteins, Signal Transducing: A broad category of carrier proteins that play a role in SIGNAL TRANSDUCTION. They generally contain several modular domains, each of which having its own binding activity, and act by forming complexes with other intracellular-signaling molecules. Signal-transducing adaptor proteins lack enzyme activity, however their activity can be modulated by other signal-transducing enzymesCarrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.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.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.Yeasts: A general term for single-celled rounded fungi that reproduce by budding. Brewers' and bakers' yeasts are SACCHAROMYCES CEREVISIAE; therapeutic dried yeast is YEAST, DRIED.Fatigue: The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli.Databases, Protein: Databases containing information about PROTEINS such as AMINO ACID SEQUENCE; PROTEIN CONFORMATION; and other properties.Sequence Analysis, Protein: A process that includes the determination of AMINO ACID SEQUENCE of a protein (or peptide, oligopeptide or peptide fragment) and the information analysis of the sequence.Systems Integration: The procedures involved in combining separately developed modules, components, or subsystems so that they work together as a complete system. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Arcuate Nucleus: A nucleus located in the middle hypothalamus in the most ventral part of the third ventricle near the entrance of the infundibular recess. Its small cells are in close contact with the ependyma.Hypothalamus: Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.Glucose Transporter Type 1: A ubiquitously expressed glucose transporter that is important for constitutive, basal GLUCOSE transport. It is predominately expressed in ENDOTHELIAL CELLS and ERYTHROCYTES at the BLOOD-BRAIN BARRIER and is responsible for GLUCOSE entry into the BRAIN.Glucose Transporter Type 4: A glucose transport protein found in mature MUSCLE CELLS and ADIPOCYTES. It promotes transport of glucose from the BLOOD into target TISSUES. The inactive form of the protein is localized in CYTOPLASMIC VESICLES. In response to INSULIN, it is translocated to the PLASMA MEMBRANE where it facilitates glucose uptake.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Peptide Library: A collection of cloned peptides, or chemically synthesized peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.