Citrate
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A citrate is an ionic form of citric acid, such as C3H5O(COO)33−, that is, citric acid minus three hydrogen ions.
Citrates are compounds containing this group, either ionic compounds, the salts, or analogous covalent compounds, esters. An example of a salt is sodium citrate and an ester is trimethyl citrate. See category for a bigger list.
Since citric acid is a multifunctional acid, intermediate ions exist, hydrogen citrate ion, HC6H5O72− and dihydrogen citrate ion, H2C6H5O7−. These may form salts as well, called acid salts.
Salts of the hydrogen citrate ions are weakly acidic, while salts of the citrate ion itself (with an inert cation such as sodium ion) are weakly basic.
Citrate is a key component in the commonly used SSC 20X hybridization buffer. There exists authoritative literature (Maniatis) that incorrectly instructs the preparation of this buffer to include 3M NaCl and 0.3M Sodium Citrate, to be titrated up with NaOH to a pH of 7. When the two components are actually mixed together, the pH is slightly basic. Therefore, the pH of the solution should instead be titrated down to 7 with HCl.
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[edit] Metabolism
[edit] TCA cycle
Citrate is an intermediate in the TCA (Krebs) Cycle. After pyruvate dehydrogenase forms acetyl CoA, by oxidative decarboxylation with five cofactors(Thiamine pyrophosphate, lipoamide, FAD, NAD+, and CoA), citrate synthase catalyzes the condensation of OAA with Acetyl CoA to form citrate. The six-carbon molecules citrate are decarboxylated to be a four-carbon molecule, succinyl CoA. The oxaloacetate are regenerated afterwards in TCA cycle and it can be used to generate another citrate molecule.
See also TCA cycle
[edit] Role in Glycolysis
High concentration of citrate can inhibit phosphofructokinase, the pace-maker of glycolysis.
[edit] See also
| Antithrombotics (thrombolytics, anticoagulants, and antiplatelet drugs) (B01) edit | ||
|---|---|---|
| Vitamin K antagonists: |
Acenocoumarol, Clorindione, Dicumarol (Dicoumarol}, Diphenadione, Ethyl biscoumacetate, Phenprocoumon, Phenindione, Tioclomarol, Warfarin | |
| Heparin group (Platelet aggregation inhibitors): |
Antithrombin III, Bemiparin, Dalteparin, Danaparoid, Enoxaparin, Heparin, Nadroparin, Parnaparin, Reviparin, Sulodexide, Tinzaparin | |
| Other Platelet aggregation inhibitors: |
Abciximab, Acetylsalicylic acid (Aspirin), Aloxiprin, Beraprost, Ditazole, Carbasalate calcium, Cloricromen, Clopidogrel, Dipyridamole, Epoprostenol, Eptifibatide, Indobufen, Iloprost, Picotamide, Prasugrel, Ticlopidine, Tirofiban, Treprostinil, Triflusal | |
| Enzymes: |
Alteplase, Ancrod, Anistreplase, Brinase, Drotrecogin alfa, Fibrinolysin, Protein C, Reteplase, Saruplase, Streptokinase, Tenecteplase, Urokinase | |
| Direct thrombin inhibitors: |
Argatroban, Bivalirudin, Dabigatran, Desirudin, Hirudin, Lepirudin, Melagatran, Ximelagatran | |
| Other antithrombotics: |
Dabigatran, Defibrotide, Dermatan sulfate, Fondaparinux, Rivaroxaban | |
| Non-medicinal: | ||
| Image:Glucose wpmp.png | This metabolism related compound article is a stub. You can help Wikipedia by expanding it. |
| This article is of interest to the Metabolic Pathways WikiProject. |
