A phospholipase is an enzyme that converts phospholipids into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C and D. Two schematic representations of a phospholipid. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid (or organic acid), often with a long aliphatic tail (long chains), either saturated or unsaturated. ... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ...

Phospholipase A (PLA)

Phospholipases A2 (PLA2s) (PDB 1CJY, EC 3.1.1.4) are a large family of enzymes that specifically deacylate fatty acids from the 2nd carbon atom (sn2, thus PLA2) of the triglyceride backbone of phospholipids, producing a free fatty acid and a lyso-phospholipid. A large range of fatty acids can be bound to the sn2 position of phospohlipids, including arachidonic acid and eicosapentaenoic acid. Image File history File links Phospholipase_A2. ... The Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Arachidonic acid is a polyunsaturated fatty acid with twenty carbons and four cis double bonds, the first at the omega-6 position (20:4n-6). ... Eicosapentaenoic acid (more commonly known as EPA; C20H30O2, all-cis-fatty acid 20:5 omega-3) is a polyunsaturated fatty acid that acts as a precursor for prostaglandin-3, which inhibits platelet aggregation) and thromboxane-3 groups. ...

Arachidonic acid is both a signalling molecule and the precursor for other signalling molecules termed eicosanoids. These include leukotrienes and prostaglandins. Some eicosanoids are synthesized from diacylglycerol, released from the lipid bilayer by phospholipase C (see below). Arachidonic acid is a polyunsaturated fatty acid with twenty carbons and four cis double bonds, the first at the omega-6 position (20:4n-6). ... In biochemistry, eicosanoids are a class of oxygenated hydrophobic cytokines that largely function as a autocrine and paracrine mediators. ... Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase. ... Chemical structure of prostaglandin E1 (PGE1). ... Diacylglycerol (DAG) is a second messenger molecule made by phospholipase C (a membrane-bound enzyme), together with inositol triphosphate. ... A diagonal molecular slab from the DPPC lipid bilayer simulation1; color scheme: PO4 - green, N(CH3)3 - violet, water - blue, terminal CH3 - yellow, O - red, glycol C - brown, chain C - grey. ...

Phospholipases A2 are ubiquitous enzymes, though the individual enzymes expression patterns differ dramatically. Initially, phospholipases A2 were named based on location of activity (e.g. pancreatic and secretory) or mode of activity (calcium dependent and calcium independent). A much more structured and accurate system has been developed based on genetic homology. For reference see (Six DA, Dennis EA. The expanding superfamily of phospholipase A(2) enzymes: classification and characterization. Biochimica et Biophysica Acta. 2000;1488(1-2):1-19).

Phospholipase B (PLB)

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Phospholipase B is said to be a mixture of both PLA1 and PLA2. It generally acts on lysolecithin (which is formed by the action of PLA2 on lecithin). The action of Phospholipase B results in the cleaving of both fatty acid residues. Lecithin, also known as Phosphatidylcholine Lecithin is mostly a mixture of glycolipids, triglycerides, and phospholipids (eg Phosphatidylcholine, Phosphatidylehtanolamine, and Phosphatidylinositol). ...

Phospholipase C (PLC)

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Phospholipase C (PDB 1AH7, EC 3.1.4.3) is a key enzyme in phosphatidylinositol (PIP₂) metabolism and lipid signaling pathways. It is activated by either G_αq protein (making it part of a G protein-coupled receptor signal transduction pathway) or by transmembrane receptors with intrinsic or associated tyrosine kinase activity. The Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Ribbon diagram of the enzyme TIM. TIM is catalytically perfect, meaning its conversion rate is limited, or nearly limited to its substrate diffusion rate. ... Phosphatidylinositol (PI), a phospholipid that is located in the plasma membrane. ... Santorio Santorio (1561-1636) in his steelyard balance, from Ars de statica medecina, first published 1614 Metabolism (from μεταβολισμος (metabolismos)) is the biochemical modification of chemical compounds in living organisms anggjgjhnd cell (b). ... Lipid signaling refers to a number of cellular signal transduction pathways that use cell membrane lipids as second messengers. ... G-proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. ... The seven transmembrane α-helix structure of a G protein-coupled receptor. ... It has been suggested that cell signaling be merged into this article or section. ... Transmembrane receptors are integral membrane proteins, which reside and operate typically within a cells plasma membrane, but also in the membranes of some subcellular compartments and organelles. ... Tyrosine kinases are a subclass of protein kinase, see there for the principles of protein phosphorylation A tyrosine kinase (EC 2. ...

It converts phosphatidylinositol to inositol triphosphate (IP₃) and diacylglycerol (DAG). These can act on other proteins in cells to increase activity of enzymes, e.g. protein kinase C, or on membrane channels such as calcium channels in the sarcoplasmic reticulum in smooth muscle. Phosphatidylinositol (PI), a phospholipid that is located in the plasma membrane. ... Inositol triphosphate or inositol 1,4,5-triphosphate (also commonly known as triphosphoinositol; abbreviated InsP3 or IP3), together with diacylglycerol, is a second messenger molecule used in signal transduction in biological cells. ... Diacylglycerol (DAG) is a second messenger molecule made by phospholipase C (a membrane-bound enzyme), together with inositol triphosphate. ... A protein kinase is an enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). ... Another, unrelated ion channeling process is part of ion implantation. ... ... Smooth muscle is a type of non-striated muscle, found within the walls of hollow organs; such as blood vessels, the bladder, the uterus, and the gastrointestinal tract. ...

The Phospholipase C family consists of PLC-δ, -β, -γ and -ε. The molecular weights of each being 85kDa for the δ form, 120-155kDa for both the β and γ forms, and 230-260kDa for the ε form. They all require calcium for catalytic activity. General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ...

PLC-δ is activated by high calcium levels and is thought to be the archetypal PLC. PLC-β is activated by G proteins. PLC-γ is activated by receptor tyrosine kinases. PLC-ε is activated by Ras. General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... G-proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. ... The receptor tyrosine kinase (RTK) family of cell surface receptors shows a high affinity to numerous growth signals. ... In molecular biology, Ras is the name of a protein, the gene that encodes it, and the family and superfamily of proteins to which it belongs. ...

All members of the family contain X and Y catalytic domains, SH2 (phosphotyrosine binding) domains are only found in the γ form, and only the ε form contains the RA (Ras Associating) domain. The -β, -δ and -γ forms all contain PH domains. Pleckstrin homology domain (PH domain) is a protein region of approximately 120 amino acids that can bind phosphoinositides (such as inositol 1,4,5-trisphosphate and phosphatidylinositol 4,5-bisphosphate), the βγ-subunits of heterotrimeric G proteins and protein kinase C. Through these interactions, the PH domain plays a role in...

Phospholipase D (PLD)

To be expanded

Phospholipase D (EC 3.1.4.50), is located in the plasma membrane and catalyzes the hydrolysis of phosphatidylcholine to form phosphatidic acid (PA) and released choline headgroup. The phosphatidic acid may itself act as a signal molecule (e.g., by activating a PA-activated kinase), or can be hydrolyzed to form diacylglycerol (DAG) by the enzyme PA phosphohydrolase The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Lecithin, also known as Phosphatidylcholine Lecithin is usually used as synonym for phosphatidylcholine, a phospholipid which is the major component of a phosphatide fraction which may be isolated from either egg yolk (in Greek lekithos - λεκιθος), or soy beans. ... // Choline is a nutrient, essential for cardiovascular and brain function, and for cellular membrane composition and repair. ... Diacylglycerol (DAG) is a second messenger molecule made by phospholipase C (a membrane-bound enzyme), together with inositol triphosphate. ...