Where is thrombin located

Thrombin is a "trypsin-like" serine protease. The thrombin A chain cleaved N terminal fragement is shown in cyan and the B chain is shown in red. The is made up of a catalytic triad of Ser, His57 and Asp, backed up by Ser A closeup shows the at which the sidechain of Asp makes a salt link with the N-terminus at residue 16, newly formed when the A chain is cleaved in the zymogen-to-enzyme activation process.

The specificity pocket is on one side of the throat of the domain 2 beta barrel, and the activation site is close next to it. The B chain consists of. As is true for all of the "trypsin-like" serine proteases, each of the two thrombin domains consists mainly of a 6-stranded, antiparallel beta barrel.

The specificity pocket here filled with the Lys sidechain of the PPACK inhibitor is in one side of the throat of the domain 2beta barrel, and the activation site is close next to it.

Binding of thrombin by sodium or at exosite I stabilizes a form of thrombin that improves substrate recognition. Rapid kinetic analysis suggests that thrombin is in a dynamic equilibrium that consists of a fast, slow, and inactive state [16].

There is question as to the physiologic relevance of the inactive state. Regardless, there will be a proportion of fast:slow thrombin and sodium binding to the fast form stabilizes that conformation.

Indeed, mutation of the residues involved in sodium binding diminishes the activity of thrombin. Antithrombin and heparin cofactor II are serpin inhibitors of thrombin that bind to specific sequences of sugar residues within a heparin chain on the endothelial lining. Central to both of these regulation pathways are specific cofactor binding at thrombins exosites; thrombomodulin and antithrombin at exosite I and heparin at exosite II.

Therefore the structure of thrombin uniquely provides it the functional properties necessary for regulation. Thrombin has a in a loop containing proline Thrombin 3D Structures. With participation by User:Cody Couperus. Category : Topic Page. Thrombin From Proteopedia. Jump to: navigation , search. Show: Asymmetric Unit Biological Assembly. Export Animated Image.

Views Article Discussion Edit this page History. It can also be because of medicines that affect blood clotting, such as heparin or argatroban. A longer thrombin time can be caused by proteins in the blood from multiple myeloma or amyloidosis. Or it could be caused by antibodies to cow thrombin, which is used as part of the testing. The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

The sample is placed in a tube containing a chemical that keeps it from clotting. Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore. Some medicines that alter blood clotting will affect your test results, such as heparin and warfarin. Tell your healthcare provider if you're taking any medicines, especially those that affect your blood's ability to clot.

Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. Search Encyclopedia. Thrombin Time Does this test have other names? The test may be used to help diagnose problems such as: Inherited conditions that lead to low fibrinogen or fibrinogen disorders Liver diseases such as cirrhosis, hepatitis, and liver cancer Cancers such as kidney cancer renal carcinoma or multiple myeloma Certain other health conditions, including lupus and ulcerative colitis Antibodies against fibrinogen your body may be making, if you had surgery that uses fibrin glue from cow sources Disseminated intravascular coagulation, a condition in which your body uses more fibrinogen Some medicines can also lead to a longer thrombin time.

You may need this test if your blood does not seem to be clotting normally. Symptoms can include: Excessive bleeding or bruising Pregnancy problems, such as repeated miscarriages early in pregnancy, and abnormal bleeding after delivery What other tests might I have along with this test?

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