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Dermorphin
Dermorphin is a hepta-peptide first isolated from the skin of South American frogs belonging to the genus ''Phyllomedusa''. The peptide is a natural opioid that binds as an agonist with high potency and selectivity to mu opioid receptors. Dermorphin is about 30–40 times more potent than morphine. The amino acid sequence of dermorphin is H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2. Dermorphin is not found in humans or other mammals and similar D-amino acid peptides have only been found in bacteria, amphibians, and molluscs. Dermorphin appears to be made in these through an unusual posttranslational modification carried out by an amino acid isomerase. This unusual process is needed because the D-alanine in this peptide is not among the 20 amino acids coded for in the genetic code and thus the peptide cannot be synthesized in the usual way from the encodings in the genome of an organism. Illicit use Dermorphin has been illegally used in horse racing as a performance-enhancing drug. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posttranslational Modification
In molecular biology, post-translational modification (PTM) is the covalent process of changing proteins following protein biosynthesis. PTMs may involve enzymes or occur spontaneously. Proteins are created by ribosomes, which translate mRNA into polypeptide chains, which may then change to form the mature protein product. PTMs are important components in cell signalling, as for example when prohormones are converted to hormones. Post-translational modifications can occur on the amino acid side chains or at the protein's C- or N- termini. They can expand the chemical set of the 22 amino acids by changing an existing functional group or adding a new one such as phosphate. Phosphorylation is highly effective for controlling the enzyme activity and is the most common change after translation. Many eukaryotic and prokaryotic proteins also have carbohydrate molecules attached to them in a process called glycosylation, which can promote protein folding and improve stability a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deltorphin I
Deltorphin I, also known as D-Ala2">small>D-Ala2eltorphin I or deltorphin C, is a naturally occurring, exogenous opioid heptapeptide and hence, exorphin, with the amino acid sequence Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2. While not known to be endogenous to humans or other mammals, deltorphin I, along with the other deltorphins and the dermorphins, is produced naturally in the skin of species of ''Phyllomedusa'', a genus of frogs native to South and Central America. Deltorphin possesses very high affinity and selectivity as an agonist for the δ-opioid receptor, and on account of its unusually high blood-brain-barrier penetration rate, produces centrally-mediated analgesic effects in animals even when administered peripherally. See also * Deltorphin Deltorphin, also known as deltorphin A and dermenkephalin, is a naturally occurring, exogenous opioid heptapeptide and thus, exorphin, with the amino acid sequence Tyr-D-Met-Phe-His-Leu-Met-Asp-NH2. Along with the other deltorp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deltorphin
Deltorphin, also known as deltorphin A and dermenkephalin, is a naturally occurring, exogenous opioid heptapeptide and thus, exorphin, with the amino acid sequence Tyr-D-Met-Phe-His-Leu-Met-Asp-NH2. Along with the other deltorphins (such as deltorphin I and deltorphin II) and the dermorphins, deltorphin is endogenous to frogs of the genus '' Phyllomedusa'' such as '' P. bicolor'' and '' P. sauvagei'' where it is produced in their skin, and is not known to occur naturally in any other species. Deltorphin is one of the highest affinity and most selective naturally occurring opioid peptides known, acting as a very potent and highly specific agonist of the δ-opioid receptor The δ-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi alpha subunit, Gi/G0 and has enkephalins as it .... Deltorphins have an unusually high blood–brain ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomerase
In biochemistry, isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which chemical bond, bonds are Bond cleavage, broken and formed. The general form of such a reaction is as follows: :\ce \quad \xrightarrow[\text] \quad \ce There is only one Enzyme substrate (biology), substrate yielding one product. This product has the same chemical formula, molecular formula as the substrate but differs in bond connectivity or spatial arrangement. Isomerases catalyze reactions across many biological processes, such as in glycolysis and carbohydrate metabolism. Isomerization Isomerases catalysis, catalyze changes within one molecule. They convert one isomer to another, meaning that the end product has the same molecular formula but a different physical structure. Isomers themselves exist in many varieties but can generally be classified as structural isomers or stereoisomerism, stereoisomers. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Performance-enhancing Drug
Performance-enhancing substances (PESs), also known as performance-enhancing drugs (PEDs), are substances that are used to improve any form of activity performance in humans. Many substances, such as anabolic steroids, can be used to improve athletic performance and build muscle, which in most cases is considered cheating by organized athletic organizations. This usage is often referred to as doping. Athletic performance-enhancing substances are sometimes referred to as ergogenic aids. Cognitive performance-enhancing drugs, commonly called nootropics, are sometimes used by students to improve academic performance. Performance-enhancing substances are also used by military personnel to enhance combat performance. Definition The classifications of substances as performance-enhancing substances are not entirely clear-cut and objective. As in other types of categorization, certain prototype performance enhancers are universally classified as such (like anabolic steroids), where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horse Racing
Horse racing is an equestrian performance activity, typically involving two or more horses ridden by jockeys (or sometimes driven without riders) over a set distance for competition. It is one of the most ancient of all sports, as its basic premise – to identify which of two or more horses is the fastest over a set course or distance – has been mostly unchanged since at least classical antiquity. Horse races vary widely in format, and many countries have developed their own particular traditions around the sport. Variations include restricting races to particular breeds, running over obstacles, running over different distances, running on different track surfaces, and running in different gaits. In some races, horses are assigned different weights to carry to reflect differences in ability, a process known as handicapping. While horses are sometimes raced purely for sport, a major part of horse racing's interest and economic importance is in the gambling associated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
An organism is any life, living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have been proposed to define what an organism is. Among the most common is that an organism has autonomous reproduction, Cell growth, growth, and metabolism. This would exclude viruses, despite the fact that they evolution, evolve like organisms. Other problematic cases include colonial organisms; a colony of eusocial insects is organised adaptively, and has Germ-Soma Differentiation, germ-soma specialisation, with some insects reproducing, others not, like cells in an animal's body. The body of a siphonophore, a jelly-like marine animal, is composed of organism-like zooids, but the whole structure looks and functions much like an animal such as a jellyfish, the parts collaborating to provide the functions of the colonial organism. The evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome
A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences (see non-coding DNA), and often a substantial fraction of junk DNA with no evident function. Almost all eukaryotes have mitochondrial DNA, mitochondria and a small mitochondrial genome. Algae and plants also contain chloroplast DNA, chloroplasts with a chloroplast genome. The study of the genome is called genomics. The genomes of many organisms have been Whole-genome sequencing, sequenced and various regions have been annotated. The first genome to be sequenced was that of the virus φX174 in 1977; the first genome sequence of a prokaryote (''Haemophilus influenzae'') was published in 1995; the yeast (''Saccharomyces cerevisiae'') genome was the first eukaryotic genome to be sequenced in 1996. The Human Genome Project ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Biosynthesis
Protein biosynthesis, or protein synthesis, is a core biological process, occurring inside Cell (biology), cells, homeostasis, balancing the loss of cellular proteins (via Proteolysis, degradation or Protein targeting, export) through the production of new proteins. Proteins perform a number of critical functions as enzymes, structural proteins or hormones. Protein synthesis is a very similar process for both prokaryotes and eukaryotes but there are some distinct differences. Protein synthesis can be divided broadly into two phases: Transcription (biology), transcription and Translation (biology), translation. During transcription, a section of DNA encoding a protein, known as a gene, is converted into a molecule called messenger RNA (mRNA). This conversion is carried out by enzymes, known as RNA polymerases, in the cell nucleus, nucleus of the cell. In eukaryotes, this mRNA is initially produced in a premature form (Primary transcript, pre-mRNA) which undergoes post-transcriptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Code
Genetic code is a set of rules used by living cell (biology), cells to Translation (biology), translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleotides at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries. The codons specify which amino acid will be added next during protein biosynthesis. With some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of genes are encoded with a single scheme (see the Codon tables, RNA codon table). That scheme is often called the canonical or standard genetic code, or simply ''the'' genetic code, though #Variations, variant codes (suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic peptides have an N-terminal (amine group) and C-terminal (carboxyl g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frog
A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough skin texture due to wart-like parotoid glands tend to be called toads, but the distinction between frogs and toads is informal and purely cosmetic, not from taxonomy (biology), taxonomy or evolutionary history. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest and associated wetlands. They account for around 88% of extant amphibian species, and are one of the five most diverse vertebrate orders. The oldest fossil "proto-frog" ''Triadobatrachus'' is known from the Early Triassic of Madagascar (250Myr, million years ago), but molecular clock, molecular clock dating suggests their divergent evolution, divergence from other amphibians may exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
