Blood clotting enzyme Essay Example for Free

Blood clotting enzyme Essay Serine protease proteins are important enzymes involved in the process of blood coagulation. Blood coagulation is an importance defense mechanism that prevents the host mammal organism from losing excess blood or from forming unwanted blood clot. The process of coagulation can be initiated by both intrinsic factors and extrinsic factors. A cascade of event is followed which activate these enzymes; normally the enzymes are inactive state a condition called zymogens. Zymogens by their virtual condition of being inactive prevent unwanted blood clotting which may have a far reaching consequence such as thrombosis. Blood clotting in a series of processes, in which the zymogens’ need to be activated by reacting with its glycoprotein co-factors. Among the serine protease is the thrombin enzyme factor five (v) responsible for clearing clot in the blood. The enzyme is usually present circulating in plasma which is made up of a single monomer chain, it life span can range from 12 to 36 hours. In human the main regulator in blood coagulation is erythrocytes leukemia cells which activate adenylate cyclase, the process is reversible by the interaction of Aalpa-thrombin with glycoprotein while b alpha enhance the platelets interaction which initiate the proteolytic process. Fibrin-bound thrombin is cleaved by thrombin at a very specific site at the extracellular N-terminal, PAR-1 regulates a number of endothelial cell biology, vascular development but more so is a mediator of thrombin signaling. The human thrombin consist of two gamma chains namely the gamma A and gamma’ the final stage of coagulation of mammalian blood involves the cleavage of the four arginine and glycine bond. Binding studies shows both fibrin 1 and fibrin 2 with low affinity to the E domain and high binding affinity at the extreme end of 408 to 425 on the gamma chain The mode of action involves conversion of fibrinogen to fibrin by breaking the bonds in the fibrinogen at a precise position of arginine and glycine where the fibrin peptides are released. The serine proteases require restructuring itself in order to fit the key and lock model. The glycine at the position five is highly conserved because it is the one which occupy the active site which is determine by the acryl group during the substrate conformation. Asparagines 189 help the enzyme to easily recognize the substrate. The active site is entirely made of histidine 57, asparagines 102, serine 195 and serine 214. The reaction on many a times prefers position 1 to position 4 during remodeling, therefore the type of protein presence to a large extend determine the kind protease and also the kind of cleavage to take place. Thrombin activation is regulated by pentapeptide of the COOH terminus of the factor (v) heavy chains. Thrombin and thrombin receptors is another regulatory point where they both posses strong protective barrier and at the same time cancerous cells were eliminated by apoptosis. A study carried out using mitochondrial membranes which were depolarized using attenuated Catalase lead to controlled cell death. Statistical finding indicate that 30% of the population carried world wide indicated that activated peptide segment at position 4 of factor eight caused a substitution in V34L after binding the structure and analyzing the interaction according to (Brenda 2010). The switching of receptor is PAR-1-dependent signaling specifically to thrombin resulting inhibition of adhesion cell surface which activate thrombin the ligand occupancy position switches the protease receptor by signaling specifically to the thrombin. Human cell in culture indicated low amount of thrombin and receptor PAR-1 agonist induced strong anti-inflammatory activities which was secondary effect of the low concentration of thrombin after activation by P13 kinase and PAR-1. Thrombin like other enzymes is very specific in the binding domain and the insertion loop which is determined by the residues involved in ligand binding as result of interaction glycoprotein and protease receptor on the platelet membrane. This uniqueness makes it very efficient in it task according to (Webert 2006). The enzyme play vital role in homeostasis, cell differentiation, thrombosis and activation of blood cell types, on exposure to phosphatidylserine on the outer surface the platelets were stimulated. A study done using heparin indicated an overlap of the active site, which was attributed to the interaction of thrombin and the gamma peptide chains to the external and the interaction to the active site in close proximity to the Na+ of the substrate. The role of the enzyme can be explained in terms of NA+ binding to thrombin on the basis of prothrombotic and procoagulant. The cascade is a continuous cycle of events that are activated by two factors ,factor (ix) and factor (viii) to form tenase complex which is discontinued by down regulation that occur in the following mechanism which include; serpin (serine protease inhibitors) which function to degrade thrombin and other activation factors, it can also be regulated by protein C where thromodulin bind to it and is inactivate in the presence of protein S, limiting the action of tissue factor by the tissue factor pathway inhibitors by inhibiting excessive TF mediated activation of factor (ix) and factor (x), plasmin help to degrade fibrin hence preventing more fibrin being formed and lastly but not the least regulation through adenylate cyclase pathway by inhibiting platelet activation by decreasing cytosol level of calcium which ultimately result to decreased release of granules which are responsible for the activation of more platelets and coagulation cascade. In conclusion the work play by thrombin enzyme is of paramount importance considering the complexity of the enzyme kinetics involved in the human body. References Brenda Enzyme database retrieved on 13 August 2010 from http://www. brenda-enzymes. org/php/result_flat. php4? ecno=3. 4. 21. 5 Furie B, Furie BC (2005). Thrombus formation in vivo. J. Clin. Invest. 115 (12): retrieved on 12 August 2010 from http://www. jci. org/cgi/content/full/115/12/3355. Webert KE, Cook RJ, Sigouin CS, (2006). The risk of bleeding in thrombocytopenic patients with acute myeloid leukemia. haematologica .

Airline Pilots Should not be Armed Essay -- essays research papers

After the events of September 11, nearly every American has thought about what it would be like to be on board an airline flight during a terrorist attack. We imagine ourselves on one of the hijacked planes and feel a surge of fear. The adrenaline rushes, the heart pounds, we go pale. If we allow the panic to escalate, we begin to feel desperate: Somebody do something! These understandable feelings of fear and desperation have moved people to argue that we should arm commercial airline pilots. Certainly it is reassuring to imagine pilots as our protectors, the last defense against crazed passengers bent on harm. Certainly we should take all reasonable measures to safeguard flights. However, is it really a good idea to let pilots act as gun-toting cowboys in the sky? When one considers the possible consequence of arming pilots, this policy does not seem at all prudent. Commercial airline pilots should concentrate on flying the plane rather than acting out a fantasy that may well turn into a nightmare. A well-trained extremist could conceivably disarm a pilot. A terrorist could als...

Compulsory education Essay

The K-12 education system is the public education system that most people are familiar with today. Comprised of 13 grades, kindergarten through 12th, it refers to the public school system in all of the United States, Canada, the United Kingdom, and parts of Europe as well. It is difficult to pinpoint the exact history of education, as it has been occurring in some form for centuries in all parts of the world. Today, K-12 education represents the compulsory education required of all children in the US. Though this type of education can be attained from either publicly or privately funded institutions, children who have reached compulsory school age (ranging from age six to eight, depending on the state) are required by law to attend school. Compulsory education in the United States began over 150 years ago when Horace Mann established a statewide system of education in Massachusetts, which became the first state to pass school attendance laws in 1852. By 1918, children were required by law to receive an education in all states. Kindergarten was actually developed prior to compulsory education. Though it is not compulsory in all states, children are required to start school in most states at the age of six. If the child is too young to start kindergarten the year he turns five, kindergarten may technically be required since he will be turning six that school year. The word kindergarten is of German origin and means â€Å"children’s garden.† The concept was the brainchild of Friedrich Froebel, a self-educated philosophical teacher, who sought to develop a place of guided play for children to â€Å"bloom.† The first kindergarten established in England was in 1852, and the United States followed by establishing its first in 1856. Though education was required of all children in Massachusetts by that time and many other states were following suit, not all schools provided, nor required, kindergarten. Similarly, not all schools required a student to stay in school beyond a certain grade, as compulsory education initially applied only to elementary aged children. Many children were also permitted to miss portions of the  school year, especially farmers’ children who were needed at home for harvesting crops and preparing for the winter. The Education Act of 1918, or the Fisher Act, was an act of British Parliament that implemented changes in progressive education and helped form many aspects of the K-12 education system used today. The Fisher Act raised the age at which children could leave school to 14 and addressed education needs, such as health inspections and accommodations for special needs children. This act also led to the development of a committee that reported to and made recommendations to policy makers regarding education. In the United States, unlike England, public education was governed by each individual state. As early as 1791, seven states had specific provisions for education in their own individual constitutions and were formed partly on the basis of education without religious bias. Prior to the passing of compulsory school attendance laws, education was primarily localized and available only to the wealthy, and it often included religious teachings. Following the compulsory attendance laws, Catholics banned together in opposition of states mandating common schooling and created private Catholic schools. In 1925, the Supreme Court ruled that children could attend public or private schools for education. Over time, each individual state developed its own department of education to oversee the public education system. Compulsory attendance grew to include kindergarten and mandate attendance through the age of 16. Funding sources for public education also grew to include federal, state and local sources. Federal funding was overseen by the United States Department of Health, Education, and Welfare from 1953 to 1979, until it was divided and the US Department of Education was formed as a stand-alone entity. By the 1950s, compulsory education had become well established, but the K-12 education system was really still in its infancy. Schools were still primarily localized, but education was no longer available only to the wealthy. Even in the 1950s, however, segregation by race was still common practice in public schools in the US. Then came another landmark decision by  the Supreme Court. In 1954, in the US Supreme Court case Brown v. Board of Education of Topeka, Kansas, the Supreme Court ruled unanimously that racial segregation in public schools was unconstitutional. Though this decision was met with resistance and it took many years before legalized segregation was completely eliminated, especially in southern states, the federal courts eventually achieved success. This achievement was not without its repercussions, and many urban and inner city schools saw an exodus of wealthy and middle-class white families, who moved to suburban districts. In time, many urban districts were left only with poor families and it became difficult to attract and pay for quality teachers and education. Since the formation of the US Department of Education in 1979, the education system has been similar to what is found today, but has undergone a series of developments and amendments to accommodate the changing needs of education. Funding has always been a source of concern for public schools, especially in poor, urban districts, where the quality of education also came into question. As a result, federal funding is now directly related to school performance as determined by standardized testing under the current No Child Left Behind Act (NCLB). NCLB was signed into law by President George W. Bush 3 January 2002. Under this law, standards of accountability were increased in an effort to improve performance and to give parents flexibility in choosing schools. NCLB requires states to administer assessments of basic skills to all students at certain grade levels and achieve the standards set forth by each state in order to receive federal funding. Specific and more rigorous goals were placed on reading achievements under this law and states also had to develop high school exit or graduation exams with specific measures of assessment in place as well. The intention was to hold schools to a higher  level of accountability, but was debated from its inception. Currently, the K-12 public education system provides a 12th grade education to eligible students for free. Families have the option of sending their children to private schools, but are then responsible for tuition. The future of education will undoubtedly experience change and social and economical challenges, just as it has in the past. Programs may soon expand to include pre-K compulsory attendance and could even expand to include options beyond the 12th grade, as these are concepts, in their earliest stages, currently being explored.

Social Research On Ethical And Political Context - 1556 Words

HSW322 Applied Social Research in ethical and political context Assessment one - Literature Review Student: Mineeka De Been FOCUS OF THE PROPOSAL The focus of this proposal is to undertake a comprehensive needs assessment of the current Barwon South West Region’s Youth Homelessness Services, with the aim of locating and bridging gaps that are presently in the services system, by collecting and analysing information such as assessment data, client interviews and so forth (Depoy Gilson, 2003, p75). This proposal will ascertain whether the Youth services in the Barwon South West region is fully addressing the barriers facing homelessness, exploring whether early intervention initiated outreach programs will engage or re-engage young people in seeking support through housing or relevant services such as mental health agencies etc. STAKEHOLDERS Key stakeholders in this needs assessment include: †¢ Homelessness Youth Services in Barwon Youth Southwest Region – specifically the Youth Entry Point workers and management, who are primarily involved in undertaking specialist assessments to gain a greater understanding of the young person’s current housing situation, who explore barriers such as Alcohol and Other Drugs (AOD), Mental Health or Family Violence concerns etc. †¢ The Minister of Housing - The Hon. 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