|
Dipeptide
A dipeptide is an organic compound derived from two amino acids. The constituent amino acids can be the same or different. When different, two isomers of the dipeptide are possible, depending on the sequence. Several dipeptides are physiologically important, and some are both physiologically and commercially significant. A well known dipeptide is aspartame, an artificial sweetener. Dipeptides are white solids. Many are far more water-soluble than the parent amino acids. For example, the dipeptide Ala-Gln has the solubility of 586 g/L more than 10x the solubility of Gln (35 g/L). Dipeptides also can exhibit different stabilities, e.g. with respect to hydrolysis. Gln does not withstand sterilization procedures, whereas this dipeptide does. Because dipeptides are prone to hydrolysis, the high solubility is exploited in infusions, i.e. to provide nutrition. Examples Commercial value About six dipeptides are of commercial interest. *Aspartame (''N''-L-α-aspartyl-L-phenyla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenortide
The xenortides (A-D) are a class of linear peptides isolated from the bacterium '' Xenorhabdus nematophila'',{{Cite journal, last=Lang, first=Gerhard, last2=Kalvelage, first2=Tim, last3=Peters, first3=Arne, last4=Wiese, first4=Jutta, last5=Imhoff, first5=Johannes F., date=2008-06-01, title=Linear and Cyclic Peptides from the Entomopathogenic Bacterium Xenorhabdus nematophilus, journal=Journal of Natural Products, volume=71, issue=6, pages=1074–1077, doi=10.1021/np800053n, pmid=18491867, issn=0163-3864 a symbiont of the entomopathogenic nematode ''Steinernema carpocapsae''. This class of compounds is known for their insect virulence and cytotoxic biological activities. The tryptamide containing compounds (xenortides B and D) show higher biological activity than the phenylethylamides (xenortides A and C). The most biologically active compound was found to be xenortide B with a potency of less than 1.6 μM activity against '' Trypanosoma brucei rhodesiense'' (sleeping sickness) and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnosine
Carnosine (''beta''-alanyl-L-histidine) is a dipeptide molecule, made up of the amino acids beta-alanine and histidine. It is highly concentrated in muscle and brain tissues. Carnosine was discovered by Russian chemist Vladimir Gulevich. Carnosine is naturally produced by the body in the liver from beta-alanine and histidine. Like carnitine, carnosine is composed of the root word ''carn'', meaning "flesh", alluding to its prevalence in meat. There are no plant-based sources of carnosine. Carnosine is readily available as a synthetic nutritional supplement. Biosynthesis Carnosine is synthesized within the body from beta-alanine and histidine. Beta-alanine is a product of pyrimidine catabolism and histidine is an essential amino acid. Since beta-alanine is the limiting substrate, supplementing just beta-alanine effectively increases the intramuscular concentration of carnosine. Physiological effects pH buffer Carnosine has a pKa value of 6.83, making it a good buffer for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ala-Gln
Alanyl-glutamine is a chemical compound which in the form L-alanyl-L-glutamine is used in dietary supplementation, in parenteral nutrition, and in cell culture. It is a dipeptide consisting of alanine and glutamine. Dieterary supplement As a dietary supplement, alanyl-glutamine protects the gastrointestinal tract. The protective effect reduces bacterial translocation, thus reducing the risk of infections and infection-related problems such as diarrhea, dehydration, malabsorption, and electrolyte imbalance. Parenteral nutrition At room temperature with 1 atmosphere of pressure, L-alanyl-L-glutamine has a solubility of about 586 g/L, which is more than 10 times glutamine's solubility (35 g/L). Also, glutamine does not withstand sterilization procedures, whereas alanyl-glutamine does. Alanyl-glutamine's high solubility makes it valuable in parenteral nutrition. Cell culture In cell culture, L-alanyl-L-glutamine is sometimes used as a replacement for L-glutamine because thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylcarnosine
''N''-Acetylcarnosine (NAC) (Not to confuse with N-Acetylcysteine) is a naturally occurring compound chemically related to the dipeptide carnosine. The NAC molecular structure is identical to carnosine with the exception that it carries an additional acetyl group. The acetylation makes NAC more resistant to degradation by carnosinase, an enzyme that breaks down carnosine to its constituent amino acids, beta-alanine and histidine. Actions Carnosine and metabolic derivatives of carnosine, including NAC, are found in a variety of tissues but particularly muscle tissue. These compounds have varying degrees of activity as free radical scavengers. It has been suggested that NAC is particularly active against lipid peroxidation in the different parts of the lens in the eye. It is an ingredient in eye drops that are marketed as a dietary supplement (not a drug) and have been promoted for the prevention and treatment of cataracts. There is scant evidence on its safety, and no convincin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anserine
Anserine (β-alanyl-''3''-methylhistidine) is a dipeptide containing β-alanine and 3-methylhistidine. Anserine is a derivative of carnosine, which has been methylated. Both anserine and carnosine are capable of chelating copper. Due to its methylation, anserine is more stable in serum and resistant to degradation than carnosine. Anserine can be found in the skeletal muscle and brain of mammals and birds. It can also be found in high levels in the human kidneys. The pKa of the imidazole ring of histidine, when contained in anserine, is 7.04, making it an effective buffer at physiologic pH. Absorption and clearance Due to its presence in lean muscles, like fish and poultry, there have been studies showing that inclusion of anserine in the diet may be beneficial for blood clearance and food absorption. These results were based on L-histidine concentrations at different time intervals. A study observing the effect of anserine diet on blood clearance and food absorption conclud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kyotorphin
Kyotorphin (L-tyrosyl-L-arginine) is a neuroactive dipeptide which plays a role in pain regulation in the brain. It was first isolated from bovine brain, by Japanese scientists in 1979. Kyotorphin was named for the site of its discovery, Kyoto, Japan and because of its morphine- (or endorphin-) like analgesic activity. Kyotorphin has an analgesic effect, but it does not interact with the opioid receptors. Instead, it acts by releasing met-enkephalin and stabilizing it from degradation. It may also possess properties of neuromediator/neuromodulator. It has been shown that kyotorphin is present in the human cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ... and that its concentration is lower in patients with persistent pain. References {{Opioidergics Dipeptid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspartame
Aspartame is an artificial non-saccharide sweetener 200 times sweeter than sucrose and is commonly used as a sugar substitute in foods and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names ''NutraSweet'', ''Equal'', and ''Canderel''. First submitted for approval as a food ingredient in 1974, aspartame was approved by the US Food and Drug Administration (FDA) in 1981. Aspartame is one of the most rigorously tested food ingredients. Reviews by over 100 governmental regulatory bodies found the ingredient safe for consumption at current levels.Food Standards Australia New Zealand: , several reviews of clinical trials showed that using aspartame in place of sugar reduces calorie intake and body weight in adults and children. Uses Aspartame is around 180 to 200 times sweeter than sucrose (table sugar). Due to this property, even though aspartame produces of energy per gram when metabolized, the quantity of aspartame ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycylglycine
Glycylglycine is the dipeptide of glycine, making it the simplest peptide. The compound was first synthesized by Emil Fischer and Ernest Fourneau Ernest Fourneau (4 October 1872 – 5 August 1949) was a French pharmacist graduated in Pharmacy 1898 for the Paris university specialist in medicinal chemical and pharmacology who played a major role in the discovery of synthetic local anesthetic ... in 1901 by boiling 2,5-diketopiperazine (glycine anhydride) with hydrochloric acid. Shaking with alkali and other synthesis methods have been reported. Because of its low toxicity, it is useful as a buffer for biological systems with effective ranges between pH 2.5–3.8 and 7.5–8.9; however, it is only moderately stable for storage once dissolved. It is used in the synthesis of more complex peptides. Glycylglycine has also been reported to be helpful in solubilizing recombinant proteins in ''E. coli''. Using different concentrations of the glycylglycine improvement in protein solubil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspartame
Aspartame is an artificial non-saccharide sweetener 200 times sweeter than sucrose and is commonly used as a sugar substitute in foods and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names ''NutraSweet'', ''Equal'', and ''Canderel''. First submitted for approval as a food ingredient in 1974, aspartame was approved by the US Food and Drug Administration (FDA) in 1981. Aspartame is one of the most rigorously tested food ingredients. Reviews by over 100 governmental regulatory bodies found the ingredient safe for consumption at current levels.Food Standards Australia New Zealand: , several reviews of clinical trials showed that using aspartame in place of sugar reduces calorie intake and body weight in adults and children. Uses Aspartame is around 180 to 200 times sweeter than sucrose (table sugar). Due to this property, even though aspartame produces of energy per gram when metabolized, the quantity of aspartame ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Sponge
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, heter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
