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| This glossary contains: 19186 medical terms |
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Enzyme
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Enzyme A cellular protein whose shape allows it to hold together several other molecules in close proximity to each other. In this way, enzymes are able to induce chemical reactions in other substances with little expenditure of energy and without being changed themselves. Basically, an enzyme acts as a catalyst.
RELATED TERMS--------------------------------------
Protein
Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur, the characteristic element being nitrogen. Proteins, the principal constituents of the protoplasm of all cells, are of high molecular weight and consist essentially of combinations of a-amino acids in peptide linkages. Twenty different amino acids are commonly found in proteins, and each protein has a unique genetically defined amino acid sequence which determines its specific shape and function. Their roles include enzymatic catalysis, transport and storage, coordinated motion, nerve impulse generation and many others.
Enzymes
Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
Enzyme
A cellular protein whose shape allows it to hold together several other molecules in close proximity to each other. In this way, enzymes are able to induce chemical reactions in other substances with little expenditure of energy and without being changed themselves. Basically, an enzyme acts as a catalyst.
Catalyst
A substance that speeds up a chemical reaction but is not consumed or altered in the process. Catalysts are of immense importance in chemistry and biology.
SIMILAR TERMS--------------------------------------
Enzyme (natural catalyst)
Any of numerous proteins and protein-nonprotein compounds that living cells produce and that can initiate, or affect the speed of, specific chemical reactions.
Enzyme defect
A disorder resulting from a deficiency (or functional abnormality) of an enzyme. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosemia, an error in the handling (metabolism) of the sugar galactose.
Enzyme linked immunosorbent assay (ELISA)
A blood test used to find Helicobacter pylori bacteria. Also used to diagnose an ulcer.
Enzyme replacement
A strategy designed to replace missing enzyme activity in a patient. This strategy currently involves the administration of a purified protein (the enzyme) by intravenous infusion.
Enzyme, lysosomal
An enzyme in an organelle (a little organ) called the lysosome within the cell. Lysosomal enzymes degrade (break down) macromolecules (large molecules) and other materials (such as bacteria) that have been taken up by the cell during the process of endocytosis. In endocytosis, macromolecules and particles from outside the cell are taken up by the cell via a progressive invagination (inpouching) and eventual pinching off of a region of the cell membrane, forming a membrane-bound vesicle (bubble) within the cytoplasm of the cell. The vesicle then fuses with the lysosome and the lysosomal enzymes carry out their appointed task of destruction (by hydrolysis). Quite amazingly, the lysosomal enzymes do not normally damage the cell itself.
Enzyme, restriction
An enzyme from bacteria that can recognize specific base sequences in DNA and cut the DNA at that site (the restriction site). A restriction enzyme acts as a biochemical scissors. Also called a restriction endonuclease. Bacteria use restriction enzymes to defend against bacterial viruses called bacteriophages (or phage). When a phage infects a bacterium, it inserts its DNA into the bacterium so that it is replicated. The restriction enzyme prevents replication of the phage DNA by cutting it into many pieces. Restriction enzymes were named for their ability to restrict, or limit, the number of strains of bacteriophage that can infect bacteria.
Enzyme-linked immunosorbent assay (ELISA)
An assay in which an enzyme is linked to an antibody and a coloured substrate is used to measure the activity of bound enzyme and, hence, the amount of bound antibody.
Enzymes
Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
Enzymes, yellow
A group of respiratory enzymes that catalyze reactions in the body permitting cells to respire or breathe. These biochemical reactions are termed oxidation-reduction reactions.
PREVIOUS AND NEXT TERMS--------------------------------------
Epithelium
A thin layer of cells that covers the internal and external surfaces of the body, including body cavities, ducts and vessels.
Erythrocyte
An erythrocyte is more commonly known as a red blood cell, which is the most numerous type of blood cell. Erythrocytes contain the red pigment hemoglobin and are responsible for oxygen transport. In humans, the number of erythrocytes in the blood varies between 4.5 and 5.5 million per cubic millimeter. They survive for about four months and are then destroyed in the spleen and liver.
Ejaculation
Ejaculation is the process of ejecting semen from the penis, and is usually accompanied by orgasm as a result of sexual stimulation. It may also occur spontaneously during sleep (called a nocturnal emission), due to stimulating of the prostate or, rarely, due to prostatic disease.
Eukaryotic
The living world is divided into two classes of organism. Eukaryotic and, much simpler, prokaryotic organisms such as bacteria. Generally eukaryotes are diploid and their cells have internal organelles, such as nuclei. Prokaryotes are haploid with much simpler cells.
Enzyme
Eicosanoid
A hormone derived from a polyunsaturated fat. Eicosanoids are made by every cell in the body. As autocrine hormones, they are constantly produced by the cell to sample the external environment. "Good" eicosanoids generate AMP.
Endocrine hormones
Hormones that are secreted from a discrete gland and then travel through the bloodstream to target tissues.
Endocrinology
The study of hormones. A more inclusive definition would be the study of biological communications.
Endocytosis
The process by which extracellular molecules (including hormones) enter a cell.
Endothelial cells
The cells that line the vascular system. They act as a barrier between the bloodstream and target cells that hormones must pass through in order to reach their receptors and exert their biological action.
RELATED TERMS--------------------------------------
Protein
Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur, the characteristic element being nitrogen. Proteins, the principal constituents of the protoplasm of all cells, are of high molecular weight and consist essentially of combinations of a-amino acids in peptide linkages. Twenty different amino acids are commonly found in proteins, and each protein has a unique genetically defined amino acid sequence which determines its specific shape and function. Their roles include enzymatic catalysis, transport and storage, coordinated motion, nerve impulse generation and many others.
Enzymes
Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
Enzyme
A cellular protein whose shape allows it to hold together several other molecules in close proximity to each other. In this way, enzymes are able to induce chemical reactions in other substances with little expenditure of energy and without being changed themselves. Basically, an enzyme acts as a catalyst.
Catalyst
A substance that speeds up a chemical reaction but is not consumed or altered in the process. Catalysts are of immense importance in chemistry and biology.
SIMILAR TERMS--------------------------------------
Enzyme (natural catalyst)
Any of numerous proteins and protein-nonprotein compounds that living cells produce and that can initiate, or affect the speed of, specific chemical reactions.
Enzyme defect
A disorder resulting from a deficiency (or functional abnormality) of an enzyme. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosemia, an error in the handling (metabolism) of the sugar galactose.
Enzyme linked immunosorbent assay (ELISA)
A blood test used to find Helicobacter pylori bacteria. Also used to diagnose an ulcer.
Enzyme replacement
A strategy designed to replace missing enzyme activity in a patient. This strategy currently involves the administration of a purified protein (the enzyme) by intravenous infusion.
Enzyme, lysosomal
An enzyme in an organelle (a little organ) called the lysosome within the cell. Lysosomal enzymes degrade (break down) macromolecules (large molecules) and other materials (such as bacteria) that have been taken up by the cell during the process of endocytosis. In endocytosis, macromolecules and particles from outside the cell are taken up by the cell via a progressive invagination (inpouching) and eventual pinching off of a region of the cell membrane, forming a membrane-bound vesicle (bubble) within the cytoplasm of the cell. The vesicle then fuses with the lysosome and the lysosomal enzymes carry out their appointed task of destruction (by hydrolysis). Quite amazingly, the lysosomal enzymes do not normally damage the cell itself.
Enzyme, restriction
An enzyme from bacteria that can recognize specific base sequences in DNA and cut the DNA at that site (the restriction site). A restriction enzyme acts as a biochemical scissors. Also called a restriction endonuclease. Bacteria use restriction enzymes to defend against bacterial viruses called bacteriophages (or phage). When a phage infects a bacterium, it inserts its DNA into the bacterium so that it is replicated. The restriction enzyme prevents replication of the phage DNA by cutting it into many pieces. Restriction enzymes were named for their ability to restrict, or limit, the number of strains of bacteriophage that can infect bacteria.
Enzyme-linked immunosorbent assay (ELISA)
An assay in which an enzyme is linked to an antibody and a coloured substrate is used to measure the activity of bound enzyme and, hence, the amount of bound antibody.
Enzymes
Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
Enzymes, yellow
A group of respiratory enzymes that catalyze reactions in the body permitting cells to respire or breathe. These biochemical reactions are termed oxidation-reduction reactions.
PREVIOUS AND NEXT TERMS--------------------------------------
Epithelium
A thin layer of cells that covers the internal and external surfaces of the body, including body cavities, ducts and vessels.
Erythrocyte
An erythrocyte is more commonly known as a red blood cell, which is the most numerous type of blood cell. Erythrocytes contain the red pigment hemoglobin and are responsible for oxygen transport. In humans, the number of erythrocytes in the blood varies between 4.5 and 5.5 million per cubic millimeter. They survive for about four months and are then destroyed in the spleen and liver.
Ejaculation
Ejaculation is the process of ejecting semen from the penis, and is usually accompanied by orgasm as a result of sexual stimulation. It may also occur spontaneously during sleep (called a nocturnal emission), due to stimulating of the prostate or, rarely, due to prostatic disease.
Eukaryotic
The living world is divided into two classes of organism. Eukaryotic and, much simpler, prokaryotic organisms such as bacteria. Generally eukaryotes are diploid and their cells have internal organelles, such as nuclei. Prokaryotes are haploid with much simpler cells.
Enzyme
Eicosanoid
A hormone derived from a polyunsaturated fat. Eicosanoids are made by every cell in the body. As autocrine hormones, they are constantly produced by the cell to sample the external environment. "Good" eicosanoids generate AMP.
Endocrine hormones
Hormones that are secreted from a discrete gland and then travel through the bloodstream to target tissues.
Endocrinology
The study of hormones. A more inclusive definition would be the study of biological communications.
Endocytosis
The process by which extracellular molecules (including hormones) enter a cell.
Endothelial cells
The cells that line the vascular system. They act as a barrier between the bloodstream and target cells that hormones must pass through in order to reach their receptors and exert their biological action.
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This dictionary contains 19186 terms.
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