|
Trehalase
The enzyme Trehalase is a glycoside hydrolase, produced by cells in the brush border of the small intestine, which catalyzes the conversion of trehalose to glucose. It is found in most animals. The non-reducing disaccharide trehalose (α-D-glucopyranosyl-1,1-α-D-glucopyranoside) is one of the most important storage carbohydrates, and is produced by almost all forms of life except mammals. The disaccharide is hydrolyzed into two molecules of glucose by the enzyme trehalase. There are two types of trehalases found in ''Saccharomyces cerevisiae'', viz. neutral trehalase (NT) and acid trehalase (AT) classified according to their pH optima NT has an optimum pH of 7.0, while that of AT is 4.5. Recently it has been reported that more than 90% of total AT activity in S. cerevisiae is extracellular and cleaves extracellular trehalose into glucose in the periplasmic space. Trehalose hydrolysis One molecule of trehalose is hydrolyzed to two molecules of glucose by the enzyme trehalase. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trehalose
Trehalose (from Turkish '' tıgala'' – a sugar derived from insect cocoons + -ose) is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it as a source of energy, and to survive freezing and lack of water. Trehalose has high water retention capabilities, and is used in food, cosmetics and as a drug. Structure Trehalose is a disaccharide formed by a bond between two α-glucose units. It is found in nature as a disaccharide and also as a monomer in some polymers. Two other stereoisomers exist: α,β-trehalose, also called ''neotrehalose'', and β,β-trehalose, also called ''isotrehalose''. Neither of these alternate isomers has been isolated from living organisms, but isotrehalose has been was found in starch hydroisolates. Synthesis At least three biological pathways support trehalose biosynthesis. An industrial process can derive trehalose from corn starch. Properties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasmic
The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are the cytosol (a gel-like substance), the cell's internal sub-structures, and various cytoplasmic inclusions. In eukaryotes the cytoplasm also includes the nucleus, and other membrane-bound organelles.The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance, or cytoplasmic matrix, that remains after the exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, plant plastids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lentztrehalose
Lentztrehaloses A, B, and C are trehalose analogues found in an actinomycete '' Lentzea'' sp. ML457-mF8. Lentztrehaloses A and B can be synthesized chemically. The non-reducing disaccharide trehalose is commonly used in foods and various products as stabilizer and humectant, respectively. Trehalose has been shown to have curative effects for treating various diseases in animal models including neurodegenerative diseases, hepatic diseases, and arteriosclerosis. Trehalose, however, is readily digested by hydrolytic enzyme trehalase The enzyme Trehalase is a glycoside hydrolase, produced by cells in the brush border of the small intestine, which catalyzes the conversion of trehalose to glucose. It is found in most animals. The non-reducing disaccharide trehalose (α-D-gluc ... that is widely expressed in many organisms from microbes to human. As a result, trehalose may cause decomposition of the containing products, and its medicinal effect may be reduced by the hydrolysis by treh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endoglycosidase H
The enzyme mannosyl-glycoprotein endo-β-''N''-acetylglucosaminidase (endoglycosidase H) () has systematic name ''glycopeptide-D-mannosyl-N4-(N-acetyl-D-glucosaminyl)2-asparagine 1,4-N-acetyl-β-glucosaminohydrolase''. It is a highly specific endoglycosidase which cleaves asparagine-linked mannose rich oligosaccharides, but not highly processed complex oligosaccharides from glycoproteins. It is used for research purposes to deglycosylate glycoproteins and to monitor intracellular protein trafficking through the secretory pathway. Structure and activity Endoglycosidase H is isolated from '' Streptomyces plicatus'' or ''Streptomyces griseus''. Its molecular mass is 29 kDa. The primary structure was described by Robbins et al. in 1984. Endoglycosidase H cleaves the bond in the diacetylchitobiose core of the oligosaccharide between two ''N''-acetylglucosamine (GlcNAc) subunits directly proximal to the asparagine residue, generating a truncated sugar molecule with one ''N''-acetyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycoprotein
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated. In proteins that have segments extending extracellularly, the extracellular segments are also often glycosylated. Glycoproteins are also often important integral membrane proteins, where they play a role in cell–cell interactions. It is important to distinguish endoplasmic reticulum-based glycosylation of the secretory system from reversible cytosolic-nuclear glycosylation. Glycoproteins of the cytosol and nucleus can be modified through the reversible addition of a single GlcNAc residue that is considered reciprocal to phosphorylation and the functions of these are likely to be an additional regulatory mechanism that controls phosphorylation-based signalling. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gel Filtration Chromatography
Size-exclusion chromatography, also known as molecular sieve chromatography, is a chromatographic method in which molecules in solution are separated by their shape, and in some cases size. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers. Typically, when an aqueous solution is used to transport the sample through the column, the technique is known as gel filtration chromatography, versus the name gel permeation chromatography, which is used when an organic solvent is used as a mobile phase. The chromatography column is packed with fine, porous beads which are commonly composed of dextran, agarose, or polyacrylamide polymers. The pore sizes of these beads are used to estimate the dimensions of macromolecules. SEC is a widely used polymer characterization method because of its ability to provide good molar mass distribution (Mw) results for polymers. Size-exclusion chromatography (SEC) is fundamentally different from all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Reading Frame
In molecular biology, reading frames are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible reading frames will be "open" (the "reading", however, refers to the RNA produced by transcription of the DNA and its subsequent interaction with the ribosome in translation). Such an open reading frame (ORF) may contain a start codon (usually AUG in terms of RNA) and by definition cannot extend beyond a stop codon (usually UAA, UAG or UGA in RNA). That start codon (not necessarily the first) indicates where translation may start. The transcription termination site is located after the ORF, beyond the translation stop codon. If transcription were to cease before the stop codon, an incomplete protein would be made during translation. In eukaryotic genes with multiple exons, introns are removed and exons are then joined together after transcription to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SDS-PAGE
SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis) is a Discontinuous electrophoresis, discontinuous electrophoretic system developed by Ulrich K. Laemmli which is commonly used as a method to separate proteins with molecular masses between 5 and 250 Kilodalton, kDa. The combined use of sodium dodecyl sulfate (SDS, also known as sodium lauryl sulfate) and polyacrylamide gel eliminates the influence of structure and charge, and proteins are separated by differences in their size. At least up to 2012, the publication describing it was the most frequently cited paper by a single author, and the second most cited overall. Properties SDS-PAGE is an electrophoresis method that allows protein separation by mass. The medium (also referred to as ′matrix′) is a polyacrylamide-based discontinuous gel. The polyacrylamide-gel is typically sandwiched between two glass plates in a slab gel. Although tube gels (in glass cylinders) were used historically, they were rapid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorylation
In biochemistry, phosphorylation is described as the "transfer of a phosphate group" from a donor to an acceptor. A common phosphorylating agent (phosphate donor) is ATP and a common family of acceptor are alcohols: : This equation can be written in several ways that are nearly equivalent that describe the behaviors of various protonated states of ATP, ADP, and the phosphorylated product. As is clear from the equation, a phosphate group per se is not transferred, but a phosphoryl group (PO3-). Phosphoryl is an electrophile. This process and its inverse, dephosphorylation, are common in biology. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Protein phosphorylation often activates (or deactivates) many enzymes. During respiration Phosphorylation is essential to the processes of both anaerobic and aerobic respiration, which involve the production of adenosine triphosphate (ATP), the "high-energy" exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Adenosine Monophosphate
Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger, or cellular signal occurring within cells, that is important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms, conveying the cAMP-dependent pathway. History Earl Sutherland of Vanderbilt University won a Nobel Prize in Physiology or Medicine in 1971 "for his discoveries concerning the mechanisms of the action of hormones", especially epinephrine, via second messengers (such as cyclic adenosine monophosphate, cyclic AMP). Synthesis The synthesis of cAMP is stimulated by trophic hormones that bind to receptors on the cell surface. cAMP levels reach maximal levels within minutes and decrease gradually over an hour in cultured cells. Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
