What is reversible phosphorylation?
146291
Reversible phosphorylation has long been an attractive mechanism to control cycles of coat assembly and disassembly during clathrin-mediated endocytosis. Many of the coat proteins are phosphorylated in vivo and in vitro. Our work has focused on the role of phosphorylation of the mu2 subunit of AP-2 (adaptor protein 2), which appears to be necessary for efficient cargo recruitment. Studies to probe the regulation of mu2 phosphorylation demonstrated that clathrin is a specific activator of the mu2 kinase, and, in permeabilized cells, cargo sequestration, driven by exogenously added clathrin, results in elevated levels of m2 phosphorylation. Furthermore, phosphorylated mu2 is mainly associated with assembled clathrin in vivo and its steady-state level is strongly reduced in cells depleted of clathrin heavy chain. Our results imply a central role for clathrin in the regulation of cargo selection via modulation of phospho-mu2 levels. This is therefore a novel regulatory role for clathrin that is independent of its structural role and that provides elegant spatial control of AP-2 and cargo interactions, ensuring that AP-2 is only activated at the correct cellular location and in the correct functional context. Ongoing studies are exploring further the roles of reversible phosphorylation in the coated vesicle cycle.
845828
Here you go...\n\nhttp://home.planet.nl/~skok/techniques/laboratory/pka_pkb.html
420068
Ubiquitination (aka ubiquinylation) is the process by which a small protein, ubiquitin, is covalently attached to lysine residues on a protein.  Often this is the first step in a process of poly-ubiquitination in which additional ubiquitin molecules are attached as a chain to the protein.  This event marks a protein for destruction by the cell's proteasome and is the cell's way of getting rid of old or improperly folded proteins.\n\nHowever, not all ubiquitinated proteins in a cell are poly-ubiquitinated.  Mono-ubiquitin modifications have been identified and appear to be important for helping the cell sort proteins to particular sites within the cell.  Once these proteins arrive at their destination, it may be important for the cell to remove the ubiquitin tag (de-ubiquitinate the protein) to allow it to function properly.\n\nTherefore, the process of mono-ubiquitination followed by de-ubiquitination is not a waste of energy, but may instead conserve energy by allowing the cell to use a series of stable ubiquitinating and de-ubiquitinating enzymes and to recycle the ubiquitin molecule rather than needing to repeatedly produce a new protein for this.
262331
It all depends on what reaction you are asking about. Are you asking a question regarding the conversion of one molecule to another in a biological system or nuclear decay which is a chemical reaction or the oxidation of a piece of coal in a furnace. If you would specify the reaction involved, I might be able to help you.
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ATP is formed by adding a phosphate group to ADP along with some energy. The process by which ATP is generated from ADP is called phosphorylation.  There are three types of phosphorylations: substrate-level, oxidative phosphorylation, and photophosporylation. \n\nEnergy stored in ATP is used in nearly all of the endergonic reactions in cells. ATP is often reffered to as the energy currency of the cell.
217358
Wee1 is a kinase which inhibits cdc2/cdk1 kinase activity, via phosphorylation at Y15.  This residue is dephosphorylated by Cdc25C phosphatase and allows entry into mitosis (or meiotic progression).  It's so called because S Pombe mutants became 'wee' or small due to the mutation of this gene, implying it's role in the cell cycle (specifically mitosis).  \n\nIt's discussed in most cell biology texts.\nie here\nhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=books&doptcmdl=GenBookHL&term=wee1+AND+mcb%5Bbook%5D+AND+106201%5Buid%5D&rid=mcb.section.3496#3501
48983
phosphorescence, this link should tell you.
920258
The cells takes up glucose that you eat.  Glucose enters Glycolysis and the Krebs Cycle.  These are both reactions that convert glucose to ATP.  ATP has three phosphate bonds.  Bonds hold atoms together and they require energy.  Our bodies then break the third phosphate bond (it holds the most energy).  When this energy is released from the bond, we can use it for energy.
456312
It is converted into ATP (adenine triphosphate).
476482
phosphoric acid is the catalyst used in the synthesis.    Its a one to one molar ratio reaction.
646590
Phosphorescence is when an atom absorbs light energy.  The energy then undergoes thermal degredation but the atom re-emits it at a lower frequency.  It's pretty cool.  Jablonski diagrams and whatnot.
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Interphase\n\nhttp://www.cellsalive.com/cell_cycle.htm
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A system is in mechanical equilibrium when the sum of the forces, and torque, on each particle of the system is zero. \n\nA system is in dynamic equilibrium  when two reversible processes occur at the same rate. Many processes (such as chemical reactions) are reversible.\n\nIn thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, and chemical equilibrium. The local state of a system at thermodynamic equilibrium is determined by the values of its intensive parameters, as pressure, temperature, etc. Specifically, thermodynamic equilibrium is characterized by the minimum of a thermodynamic potential, such as the Helmholtz free energy, i.e. systems at constant temperature and volume:\n\nA = U – TS \nOr as the Gibbs free energy, i.e. systems at constant pressure and temperature:\n\nG = H – TS \nThe process that leads to a thermodynamic equilibrium is called thermalization. An example of this is a system of interacting particles that is left undisturbed by outside influences. By interacting, they will share energy/momentum among themselves and reach a state where the global statistics are unchanging in time.\n\n\n\nChemical equilibrium is the state in which the concentrations of the reactants and products have no net change over time. Usually, this state results when the forward chemical reactions proceed at the same rate as their reverse reactions. The rates of the forward and reverse reactions are generally not zero but, being equal, there are no net changes in any of the reactant or product concentrations. This process is known as dynamic equilibrium (Atkins & Jones, 2001). Fundamentally, reactions do not go fully to completion, but reach an equilibrium, because of the entropy of mixing associated with reaction.
723838
ATP maybe.\nGlucose if not.
157808
It's a molecule of PO4.  These can link to an -OH moiety on a sugar or nucleotide molecule, or they can link to another phosphate group.  When they link to another phostphate group, the bond is a high-energy bond.  Hence AMP, ADP, and ATP are all adensine with either 1, 2, or 3 linked phosphate groups.  ATP has the most energy, and the act of removing either one or two phosphates from the ATP can be coupled with some other process taht isn't energetically favorable, in order to power important changes.  That's why ATP is used as the primary power source of the cell.\n\nThe shape of the phosphate ion is a phosphorus atom surrounded by 4 oxygen atoms.  One oxygen is double-bonded, and the other four oxygens have a negative charge (ie, H3PO4 usually loses its hydrogen in solution, and hence phosphoric acid is highly acidic).\n\nPhosphate in solution is usually denoted as Pi (P with an I subscript) meaning "inorganic phosphate."  There is a lot of this floating around in biological systems.  You'll usually see something like\n\nATP --> ADP + Pi\n\nto denote the loss of a phosphate group by adensine.
36291
alright i got this one for you right off the top of my head...\n\nfirst off i think you are talking about a receptor tyrosine kinase (RTK).  \n\nthings to know about an RTK: 1. a kinase is an enzyme that adds a phosphate to something else. 2. a receptor binds a ligand and leads to a signal activation.  3.  tyrosine is an amino acid that is found in the intracellular portion of a receptor tyrosine kinase.  4.  a membrane bound receptor is something that is encased inside the cell membrane. aka part of it is outside the cell and part of it is insdie the cell.\n\nso an RTK is a membrane bound receptor which receives an extracellular ligand and when the ligand binds the receptor a cross phosphorlyation event occurs in the intracellular portion of the receptor tyrosine kinase.  if you dont know what i'm talking about view the diagram below:\n\nextracellar space (outside of cell)\n+  <--Ligand aka extracellular signal\n&#92;/ <--- receptor portion of Receptor tyrosine kinase\n{}=====   <-- cell membrane  wraps around in a circle\n[]  <--kinase portion of receptor tyronsine kinase\nPxP <--- cross phosphorylation \n\n\nintracellular space (inside the cell)\n============ <-- more cell membrane that connects with the other cell memebrane\nextracellular space\n\n\nwhen the ligand (the + in the diagram) binds the receptor the cross phosphorylation occurs and then the signal proceeds via other chemical reactions into the nucleus where the DNA is housed.  \n\nWHY is this such a big deal?????  because this is the mechanism for how a cell is told to divide!  so basically when there is ligand present outside the cell and it hits the receptor then the cell divides.   the big point is that when the receptor does not work properly and the cross phosphorylation occurs IN THE ABSENCE of LIGAND then the tyrosine kinases is degregulated and this LEADS TO CANCER. \n\nwhy and how does it become deregulated and cross phosphorylate with out having to bind ligand?  mainly b/c the tyrosine kinase is defective when it is made by the cell.  This can happen because the DNA which is the blueprint or directions on how to make the tyrosine kinase is altered so that it shows the cell how to make a faulty or mutant tyrosine kinase.  Then it sticks this tyrosine kinase on the membrane but instead of waiting for ligand it just cross phosphorylates on its own and this leads to cancer.  \n\nI wrote sooo much i dont know if this helps.  but i doubt you will get a more complete answer to your question.  if you want a short quick answer. then it would be mutation in the DNA makes a bad tyrosine kinases which tells the cell to divide with out control.
530652
There is no such thing as reverse gluconeogenesis. If there was, then your body would quickly wither away, as there would be no sugar. Pyruvate/lactate -> glucose -> atp just like that.\n\n**glycolysis is the closest thing to reverse gluconeogenesis**