生物化學(xué)詞匯

Active center. 活性中心 A specialized region of an enzyme where the enzyme interacts with the substrate and catalyzes its conversion to products. Many aminoacyl residues contribute to the active center. Adenylyl cyclase. 腺苷酸環(huán)化酶 An enzyme that catalyzes the synthetic reaction of cyclic AMP from ATP in response to hormones such as epinephrine and glucagon. Alanine-glucose cycle. 丙氨酸-葡萄糖循環(huán) A cooperative pathway between liver and muscle in which the ammonia and carbon from amino acid metabolism are removed from the muscle as alanine, taken up by the liver, transaminated to pyruvate, converted into glucose, and shipped out back to the muscle. albumin. 清蛋白 Albumin makes up 50% to 55% of the proteins of plasma and is thought to be the main contributor to osmotic pressure of blood. Another important function is that albumin has very broad and non-specific binding properties. Allosteric enzyme. 變構(gòu)酶 Allosteric enzymes are enzymes whose activity at the catalytic site may be modulated by the presence of allosteric effectors at an allosteric site. Allosteric means “occupy another space”, so an allosteric effector occupy another space, giving an effect on enzymes. Allosteric regulation. 變構(gòu)調(diào)節(jié) A type of enzyme regulation in which an effector binds to one site on the enzyme and increase or decreases the activity at another site. Allosteric regulation provides a rapid means for regulation of their activity. Aminoacyl-tRNA synthetase. 氨基酰tRNA合成酶 The enzymes are responsible for the recognition and attachment of the 20 amino acids to specific tRNA. Anticodon. 反密碼子 The template-recognition site on tRNA is a sequence of three bases called the anticodon, which recognizes a complementary sequence of three bases on mRNA. Apoprotein.載脂蛋白 The protein moiety of a lipoprotein. They mediate the interaction between lipoproteins and tissues. Apoptosis. 細(xì)胞凋亡 Programmed cell death. The programmed cell death is tightly regulated, which plays important roles in physiologic processes. Typical morphologic changes can be observed in apoptosis. One or more endonucleases degrade DNA, leading to characteristic ladder of discrete DNA fragment on electrophoresis. Bile salts. 膽汁酸鹽 Salt form of bile acids and their conjugates. Since bile contains significant quantities of sodium and potassium and the pH is alkaline, it is assumed that the bile acids and their conjugates are in a salt form, so called “bile salts.” Biotin. 生物素 A cofactor involved in carboxylation reactions. Most enzymes that catalyze the ATP-dependent addition of CO2 to a substrate (like acetyl-CoA carboxylase) requires the cofactor biotin. Calcitonin. 降鈣素 A 32-amino-acid peptide secreted by the parathyroid. The dominant biological action of calcitonin is to mediate a lowering of serum calcium levels. The hypocalcemic and hypophosphatemic effects of calcitonin are believed to be due to an inhibition of PTH-mediated calcium resorption. Calcium-binding protein. 鈣結(jié)合蛋白 1,25(OH)2-D3 stimulates gene transcription and formation of specific mRNA that codes for “calcium-binding protein”, also called “Calbindin”. Three distinct vitamin D-induced “Calbindin” have been isolated. Two of them are found exclusively inside the intestinal and kidney cells, which are actively involved in calcium translocation. Calmodulin. 鈣調(diào)蛋白 A ubiquitous calcium sensor in eukaryotes, regulates the activities of many intracellular proteins. The binding of Ca2+ to multiple sites in calmodulin induces a major conformational change that converts it from an inactive to an active form. Activated calmodulin binds to many enzymes and modifies their activities. cAMP. 環(huán)化腺苷一磷酸 Second messenger for increased demand for energy and glucose. cAMP activates cAMP-dependent protein kinase. Increased cAMP levels are associated with increased protein phosphorylation. Increases in the cAMP concentration cause activation of glycogen degradation, increased fatty acid breakdown, stimulation of glycolysis in muscle, and stimulation of gluconeogenesis in the liver. cAMP-dependent protein kinase，PKA. 依賴cAMP的蛋白激酶 Most effects of cyclic AMP in eukaryotic cells are mediated by the activation of a single protein kinase. This key enzyme is called protein kinase A or cAMP-dependent protein kinase, which alters the activities of target proteins by phosphorylating specific serine or threonine residues. Capping. 帽子生成 Putting a 7-methylguanosine triphosphate on the 5 end of an mRNA molecule. Capping is involved in the recognition of mRNA and may increase the stability of the RNA by preventing the attack of 5exonucleases. Carnitine shuttle. 肉堿穿梭 Gets fatty acyl groups into mitochondria. Fatty acyl-CoA in the cytosol is transferred to carnitine to make fatty acyl carnitine, which is transported into mitochondria. Once inside, the fatty acyl group is transferred to CoA and the carnitine is returned to the mitochondrial membrane.Catabolic pathway. 分解代謝途徑 Degradative metabolism. Catabolic pathways involve oxidative processes that release free energy. Catabolic repression. 分解代謝阻遏 Catabolic repression means that an intermediate in a sequence of catabolic enzyme-catalyzed reactions has ability to repress synthesis of catabolic enzymes. Catabolite gene activator protein, CAP. 分解（代謝）物基因激活蛋白 A cAMP-binding protein that is capable of stimulating transcription by binding to certain promoter sites. It consists of two subunits, each of which contains a DNA-binding domain and a cAMP binding domain. cDNA library. cDNA文庫 A library is a collection of recombinant clones. cDNA library represents the population of mRNA in a tissue. See also cDNA. cDNA. 互補(bǔ)DNA Complementary DNA. cDNA copies from a population of cytoplasmic mRNA using enzyme reverse transcriptase, converting the cDNA single strands to double-stranded DNA. The reverse transcriptase copies RNA templates into DNA-RNA hybrids. After the RNA in these hybrids is specifically destroyed, double-stranded DNA may be produced by DNA polymerase. cDNA is a copy of an mRNA so that it contains only the exon sequences. cis-acting element. 順式作用元件 This word described the regulatory interactions between two DNA sequences on the same gene. An enhancer or repressor sequence in the DNA is a cis-acting element or factor that affects the transcription of the gene. cistron. 順反子 A stretch of DNA that carries the information for a polypeptide chain is called cistron. Clone. 克隆 Group of cells or sequences of DNA that are identical with a single parental cell or molecule. Coding strand. 編碼鏈 The coding strand of DNA has the same sequence as that of the RNA transcript except for T in place of U. It is so-called because it matches the RNA transcript that encodes the protein. The coding strand is also known as the sense strand. codon. 密碼子 Each amino acid in a protein is specified by an mRNA sequence of three nucleotides, which is called a codon. Coenzyme. 輔酶 A molecule bound to an enzyme and is essential for its activity. The coenzymes allow the enzyme to have functional groups that are not available from the side chains of the amino acids. Competitive inhibition. 競(jìng)爭性抑制 Substrate and inhibitor combine at the same site and result in raising the apparent Km for the substrate. In competitive inhibition, inhibitor can be completely displaced by a high concentration of the substrate. Configuration. 構(gòu)型 The stereochemical arrangement of atoms in a molecule. Configuration cannot be changed without breaking and reforming covalent bonds. Conformation. 構(gòu)象 Differences in rotation around bonds. The conformation of a molecular can be changed by simply rotating groups around single bonds. Conjugated bilirubin. 結(jié)合膽紅素 Adding glucuronic acid molecules to bilirubin. Hepatocytes perform the process and convert bilirubin to a water-soluble form. Cosmid vector. 柯斯質(zhì)粒載體 A special class of artificially constructed E.coli plasmids that carry the cos site, which allows them to be packaged intophage particles for efficient introduction into bacteria. Creatine kinase. 肌酸激酶 Kinases incorporate phosphate from ATP into the substrate. Creatine kinase converts creatine to creatine phosphate, a major energy reserves in muscle. de novo synthesis. 從頭合成 Biosynthesis of nucleotides with simple materials. Purine and pyrimidine ribonucleotides are synthesized via two pathways, in which the purines are built as nucleotides via phosphoribosyl intermediates, whereas the pyrimidine ring is completed to the stage of orotate before coupling to ribose. degenerate. 簡并 More than one codon can specify the same amino acid and all codons are unambiguous in that each specifies no more than one amino acid. Denaturation. 變性 Destroy the secondary, tertiary, and quaternary structure of a protein, DNA, or RNA molecule. DNA damage. DNA損傷 DNA damage is that changes in the DNA sequence resulted from copying errors and the effects of various physical and chemical agents or carcinogens，which alters one or more nucleotides in DNA. DNA polymerase. DNA聚合酶 The principal synthetic enzyme, DNA polymerase, extends the primers in the 5 to 3 direction by catalyzing addition of deoxyribonucleoside 5-phosphates to the primer 3ends. Synthesis proceeds in the 5 to 3 direction as the template strand is read in the 3 to 5 direction. DNA Replication. DNA復(fù)制 Generation of a new copy of double-stranded DNA from a parental DNA molecule. Domain. 結(jié)構(gòu)域 Some polypeptide chains fold into two or more compact supersecondary structures. These compact globular supersecondary structures are called domains, which is one level of proteins structures between secondary structure and tertiary structure.Effector. 效應(yīng)劑 A class of small molecules capable of binding at a regulatory site. The binding of an effector changes the conformation of the enzyme so as to alter the kinetic properties of the catalytic site. Enhancer. 增強(qiáng)子 The sequence elements that can increase the rate of transcription initiation of eukaryotic genes. Enhancers have no promoter activity of their own but they can exert their stimulatory actions over distances of several thousand base pairs. Enterohepatic circulation. 腸肝循環(huán) The primary bile acids are synthesized in the liver and the secondary bile acids are formed in the intestine. The secondary bile acids are absorbed in the intestine, returning to the liver then recycle between intestine and liver, which is known as the entero-hepatic circulation. Epidermal growth factor (EGF) . 表皮生長因子 Epidermal growth factor can stimulates growth of many epidermal and epithelial cells. Also see “growth factor”. Essential amino acid. 必需氨基酸 The amino acids that humans can not synthesize. The human diet must contain these amino acids to support growth or maintain health. exon. 外顯子 Regions that are retained in the mature RNA. FAD. 黃素腺嘌呤二核苷酸 Flavin Adenine Dinucleotide. FAD is derived from vitamin riboflavin, which serves as cofactor for oxidation and reduction reactions. Fat. 脂肪 Mainly stored as triglyceride in adipose tissue. The adipose tissue releases fatty acids by the activation a hormone-sensitive lipase that catalyzes the hydrolysis of the triglyceride. The fatty acids are then transported through the serum and oxidized via b oxidation in the tissues to yield energy. Feedback inhibition . 反饋抑制 Feedback inhibition refers to the inhibition of the activity of an enzyme in a biosynthetic pathway by an end product of that pathway. Ferritin. 鐵蛋白 Intracellular form of iron storage. It stores iron that can be used as condition requires. FH4. 四氫葉酸 Tetrahydrofolate. A reduced form of folic acid involved intimately in one-carbon transfer reactions. Gene. 基因 A stretch of DNA that carries the information for a polypeptide chain is called gene or cistron. Also see cistron. Genome. 基因組 Total information of gene contained in a cell, an organism or a virus. Genomic DNA library. 基因組DNA文庫 Fragments of DNA from the genome of some organism. They are prepared from the total DNA of a cell line or tissue by performing partial digestion of total DNA with a restriction enzyme that cuts DNA frequently. It contains exons, introns, untranslated regions that can occur in DNA. Glucogenic amino acid. 生糖氨基酸 The amino acid that yield pyruvate or citric cycle intermediates. Gluconeogenesis. 糖異生 Making glucose or glycogen from noncarbohydrate. The term used to include all mechanisms and pathways responsible for converting noncarbohydrate to glucose or glycogen. Glycerol-a-phosphate shuttle. a-磷酸甘油穿梭 Get electron from cytoplasmic NADH into the mitochondria so that 2 ATPs can be made by oxidation of the NADH. The enzymes of the shuttle in mitochondria is linked to the respiratory chain via a flavoprotein. Glycolysis. 酵解 Metabolic pathway that provides pyruvate as fuel to the citric cycle or for fat synthesis. In the absence of oxygen, lactate is produced from the pyruvate to regenerate NAD+ so that the pathway can continue to work in the absence of oxygen. Gout. 痛風(fēng) It is an inherited metabolic disease that affects the joints and kidneys caused by hyperuricemia. Though some patients have a partial deficiency of hypoxanthine-guanine phosphoribosyl transferase (HGPRT), it is not sole cause of the disease. Growth factor. 生長因子 Small polypeptides (more properly called cytokines) that stimulate the growth of particular classes of cells. The factors have a variety of effects, including changes in the uptake of small molecules, initiation or stimulation of the cell cycle, and ultimately cell division. Examples of secreted cytokines are EGF (epidermal growth factor), PDGF (platelet-derived growth factor), and insulin. Guide RNA. 指導(dǎo)RNA Guide RNA is a sequence that is complementary to the correctly edited mRNA. Hairpin structure. 發(fā)夾結(jié)構(gòu) A double-helical stretch formed by base paring between neighboring complementary sequences of a single strand of DNA or RNA. Helicase. 解鏈酶 An enzyme whose activity involved in DNA replication that relieves the strain associated with unwinding the DNA double helix during replication. Heme. 血紅素 A cofactor consisting of a porphyrin ring containing an iron atom. Heme has different functions depending on the protein that used them as a cofactor. Heme are used to carry oxygen without oxidizing it in hemoglobin and myoglobin, but in other proteins, like cytochrome P450, the heme iron produces a very reactive iron-oxygen species at the active site.Hemoglobin. 血紅蛋白 Hemoglobin is the oxygen-carrying system found in erythrocytes, which transports oxygen from the lungs to all tissues of the body. The quaternary structure of hemoglobin confers its allosteric properties that adapt it to its biologic roles and permit its precise regulation. Hexokinase. 己糖激酶 Responsible for the phosphorylation of glucose for entry into glycolysis, glycogen synthesis, or the pentose phosphate pathway. hnRNA. 不均一核內(nèi)RNA Heterogeneous nuclear RNA. They are formed in the nucleus that is a precursor to mRNA, which has both the intron and exon sequences. Hormone response element, HRE. 激素反應(yīng)元件 A specific DNA sequences capable of binding activated receptors. These elements regulate the gene expression. Both steroids and peptide hormones exert their effects on transcription through HREs, but the initial reactions are different. Housekeeping gene. 管家基因 The genes that are expressed at a reasonably constant rate and not known to be subject to regulation. Induction. 誘導(dǎo) Synthesis of a particular protein in response to a signal stimulation in cellular metabolism. For example, the synthesis of an enzyme can be induced by its substrate. Intron. 內(nèi)含子 The mosaic nature of eukaryotic genes is discontinuous. The primary transcript of a gene contains the regions that are not present in the mRNA. Regions that are removed from the primary transcript are called introns. Isoelectric point. 等電點(diǎn) The pH at which a molecule has a net zero charge. Isomerase. 異構(gòu)酶 An enzyme that catalyzes an intramolecular rearrangement. Isozyme. 同工酶 Distinct physical forms of an enzyme with the same catalytic activity. Separation and identification of isozymes is of diagnostic value. Jaundice. 黃疸 When bilirubin in the blood reaches a certain concentration, hyperbilirubinemia exists and bilirubin diffuses into the tissues, which then became yellow. The condition is called jaundice. Ketogenic amino acid. 生酮氨基酸 An amino acid that yields only acetyl-CoA. They can not yield pyruvate or tricarboxylic acid cycle intermediates. Ketone bodies. 酮體 Acetoacetate, hydroxybutyrate and acetone. At high rate of fatty acid oxidation, the liver produces considerable quantities of acetoacetate and hydroxybutyrate. The former continually undergoes spontaneous decarboxylation to yield acetone. Ketone bodies are metabolized in muscle and brain as an energy source. Km. 米氏常數(shù) If an enzyme follows hyperbolic kinetics, the Km is equal to the substrate concentration at which the reaction rate is half its maximal value. Ligase. 連接酶 A ligase catalyzes the joining of two pieces of DNA covalently. DNA ligase joins the backbone phosphates in a phosphodiester bond. Lipids. 脂類 Lipids consist of a diverse set of hydrophobic molecules including triglycerides, phospholipids, steroids, and so forth. It is soluble in organic solvents like chloroform or ether. Malate-Aspartate shuttle. 蘋果酸-天冬氨酸穿梭 Gets electrons from cytoplasmic NADH into the mitochondria so that 3 ATPs can be produced