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Phosphodiester Bond
In chemistry, a phosphodiester bond occurs when exactly two of the hydroxyl groups () in phosphoric acid react with hydroxyl groups on other molecules to form two ester bonds. The "bond" involves this linkage . Discussion of phosphodiesters is dominated by their prevalence in DNA and RNA, but phosphodiesters occur in other biomolecules, e.g. acyl carrier proteins, Phospholipid, phospholipids and the cyclic forms of GMP and AMP (Cyclic guanosine monophosphate, cGMP and Cyclic adenosine monophosphate, cAMP). Phosphodiester Backbone of DNA and RNA Phosphodiester bonds make up the Polymer backbone, backbones of DNA and RNA. In the phosphodiester bonds of nucleic acids, a phosphate is attached to the 5' carbon of one nucleoside and to the 3' carbon of the adjacent nucleoside. Specifically, it is the phosphodiester bonds that link the Directionality (molecular biology), 3' carbon atom of one sugar molecule and the 5' carbon atom of another (hence the name 3', 5' phosphodiester linkag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Polymerase I
DNA polymerase I (or Pol I) is an enzyme that participates in the process of prokaryotic DNA replication. Discovered by Arthur Kornberg in 1956, it was the first known DNA polymerase (and the first known of any kind of polymerase). It was initially characterized in '' E. coli'' and is ubiquitous in prokaryotes. In ''E. coli'' and many other bacteria, the gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ... that encodes Pol I is known as ''polA''. The ''E. coli'' Pol I enzyme is composed of 928 amino acids, and is an example of a processive enzyme — it can sequentially catalyze multiple polymerisation steps without releasing the single-stranded template. The physiological function of Pol I is mainly to support repair of damaged DNA, but it also contributes to connectin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known forms of life, it is often referred to as the "molecular unit of currency" for intracellular energy transfer. When consumed in a Metabolism, metabolic process, ATP converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. It is also a Precursor (chemistry), precursor to DNA and RNA, and is used as a coenzyme. An average adult human processes around 50 kilograms (about 100 mole (unit), moles) daily. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of three parts: a sugar, an amine base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Replication
In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all life, living organisms, acting as the most essential part of heredity, biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential. DNA is made up of a nucleic acid double helix, double helix of two Complementary DNA, complementary DNA strand, strands. DNA is often called double helix. The double helix describes the appearance of a double-stranded DNA which is composed of two linear strands that run opposite to each other and twist together. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphodiesterase Inhibitor
A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), thereby preventing the inactivation of the intracellular second messengers, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) by the respective PDE subtype(s). The ubiquitous presence of this enzyme means that non-specific inhibitors have a wide range of actions, with those in the heart and lungs being some of the first to find therapeutic use. History The different forms or subtypes of phosphodiesterase were initially isolated from rat brains in the early 1970s and were soon afterward shown to be selectively inhibited in the brain and in other tissues by a variety of drugs. The potential for selective phosphodiesterase inhibitors as therapeutic agents was predicted as early as 1977 by Weiss and Hait. This prediction meanwhile has proved to be true in a variety of fields. Classification Nonselective PDE inhibitors Methylated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Translation (biology)
In biology, translation is the process in living Cell (biology), cells in which proteins are produced using RNA molecules as templates. The generated protein is a sequence of amino acids. This sequence is determined by the sequence of nucleotides in the RNA. The nucleotides are considered three at a time. Each such triple results in the addition of one specific amino acid to the protein being generated. The matching from nucleotide triple to amino acid is called the genetic code. The translation is performed by a large complex of functional RNA and proteins called ribosomes. The entire process is called gene expression. In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later protein folding, folds into an Activation energy, active protein and performs its functions in the cell. The polypeptide can also start folding during protein synthesis. The ribosome facilitates decoding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription (biology)
Transcription is the process of copying a segment of DNA into RNA for the purpose of gene expression. Some segments of DNA are transcribed into RNA molecules that can encode proteins, called messenger RNA (mRNA). Other segments of DNA are transcribed into RNA molecules called non-coding RNAs (ncRNAs). Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a Complementarity (molecular biology), complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, Antiparallel (biochemistry), antiparallel RNA strand called a primary transcript. In virology, the term transcription is used when referring to mRNA synthesis from a viral RNA molecule. The genome of many Orthornavirae, RNA viruses is composed of Sense (molecular biology), negative-sense RNA which acts as a template for positive sense viral messenger RNA - a necessary step in the synthesis of viral proteins needed for viral replication. This process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribonucleotide
In biochemistry, a ribonucleotide is a nucleotide containing ribose as its pentose component. It is considered a molecular precursor of nucleic acids. Nucleotides are the basic building blocks of DNA and RNA. Ribonucleotides themselves are basic monomeric building blocks for RNA. Deoxyribonucleotides, formed by reducing ribonucleotides with the enzyme ribonucleotide reductase (RNR), are essential building blocks for DNA. There are several differences between DNA deoxyribonucleotides and RNA ribonucleotides. Successive nucleotides are linked together via phosphodiester bonds. Ribonucleotides are also utilized in other cellular functions. These special monomers are utilized in both cell regulation and cell signaling as seen in adenosine-monophosphate ( AMP). Furthermore, ribonucleotides can be converted to adenosine triphosphate ( ATP), the energy currency in organisms. Ribonucleotides can be converted to cyclic adenosine monophosphate (cyclic AMP) to regulate hormones in organisms as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaline Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and water molecule to split into two parts. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphodiesterase
A phosphodiesterase (PDE) is an enzyme that breaks a phosphodiester bond. Usually, ''phosphodiesterase'' refers to cyclic nucleotide phosphodiesterases, which have great clinical significance and are described below. However, there are many other families of phosphodiesterases, including phospholipases C and D, autotaxin, sphingomyelin phosphodiesterase, DNases, RNases, and restriction endonucleases (which all break the phosphodiester backbone of DNA or RNA), as well as numerous less-well-characterized small-molecule phosphodiesterases. The cyclic nucleotide phosphodiesterases comprise a group of enzymes that degrade the phosphodiester bond in the second messenger molecules cAMP and cGMP. They regulate the localization, duration, and amplitude of cyclic nucleotide signaling within subcellular domains. PDEs are therefore important regulators of signal transduction mediated by these second messenger molecules. History These multiple forms (isoforms or subtypes) of phosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of Biomolecule, biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyamine
A polyamine is an organic compound having two or more amino groups. Alkyl polyamines occur naturally, but some are synthetic. Alkylpolyamines are colorless, hygroscopic, and water soluble. Near neutral pH, they exist as the ammonium derivatives. Most aromatic polyamines are crystalline solids at room temperature. Natural polyamines Low-molecular-weight linear polyamines are found in all forms of life. The principal examples are the triamine spermidine and the tetraamine spermine. They are structurally and biosynthetically related to the diamines putrescine and cadaverine. Polyamine metabolism is regulated by the activity of the enzyme ornithine decarboxylase (ODC). Polyamines are found in high concentrations in the mammalian brain. File:Spermidine-2D-skeletal.svg, spermidine File:Spermine.svg, spermine Synthetic polyamines Ethyleneamines are a commercially-important class of synthetic polyamines with ethylene ( linkages); global production capacity was estimated at 385,00 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
