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Trypsin

Trypsin is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated. Trypsin cleaves peptide chains at the carboxyl side of the amino acids lysine or arginine, it is used for numerous biotechnological processes. The process is referred to as trypsin proteolysis or trypsinisation, proteins that have been digested/treated with trypsin are said to have been trypsinized. Trypsin was discovered in 1876 by Wilhelm Kühne and was named from the Ancient Greek word for rubbing since it was first isolated by rubbing the pancreas with glycerin. In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides; the peptide products are further hydrolyzed into amino acids via other proteases, rendering them available for absorption into the blood stream. Tryptic digestion is a necessary step in protein absorption, as proteins are too large to be absorbed through the lining of the small intestine.

Trypsin is produced as the inactive zymogen trypsinogen in the pancreas. When the pancreas is stimulated by cholecystokinin, it is secreted into the first part of the small intestine via the pancreatic duct. Once in the small intestine, the enzyme enteropeptidase activates trypsinogen into trypsin by proteolytic cleavage; the enzymatic mechanism is similar to that of other serine proteases. These enzymes contain a catalytic triad consisting of histidine-57, aspartate-102, serine-195; this catalytic triad was called a charge relay system, implying the abstraction of protons from serine to histidine and from histidine to aspartate, but owing to evidence provided by NMR that the resultant alkoxide form of serine would have a much stronger pull on the proton than does the imidazole ring of histidine, current thinking holds instead that serine and histidine each have equal share of the proton, forming short low-barrier hydrogen bonds therewith. By these means, the nucleophilicity of the active site serine is increased, facilitating its attack on the amide carbon during proteolysis.

The enzymatic reaction that trypsin catalyzes is thermodynamically favorable, but requires significant activation energy. In addition, trypsin contains an "oxyanion hole" formed by the backbone amide hydrogen atoms of Gly-193 and Ser-195, which through hydrogen bonding stabilize the negative charge which accumulates on the amide oxygen after nucleophilic attack on the planar amide carbon by the serine oxygen causes that carbon to assume a tetrahedral geometry; such stabilisation of this tetrahedral intermediate helps to reduce the energy barrier of its formation and is concomitant with a lowering of the free energy of the transition state. Preferential binding of the transition state is a key feature of enzyme chemistry; the positive aspartate residue located in the catalytic pocket of trypsin is responsible for attracting and stabilizing negatively charged lysine and/or arginine, is, responsible for the specificity of the enzyme. This means that trypsin predominantly cleaves proteins at the carboxyl side of the amino acids lysine and arginine except when either is bound to a C-terminal proline, although large-scale mass spectrometry data suggest cleavage occurs with proline.

Trypsin is considered an endopeptidase, i.e. the cleavage occurs within the polypeptide chain rather than at the terminal amino acids located at the ends of polypeptides. Human trypsin has an optimal operating temperature of about 37 °C. In contrast, the Atlantic cod has several types of trypsins for the poikilotherm fish to survive at different body temperatures. Cod trypsins include trypsin I with an activity range of 4 to 65 °C and maximal activity at 55 °C, as well as trypsin Y with a range of 2 to 30 °C and a maximal activity at 21 °C; as a protein, trypsin has various molecular weights depending on the source. For example, a molecular weight of 23.3 kDa is reported for trypsin from porcine sources. The activity of trypsin is not affected by the enzyme inhibitor tosyl phenylalanyl chloromethyl ketone, TPCK, which deactivates chymotrypsin; this is important because, in some applications, like mass spectrometry, the specificity of cleavage is important. Trypsin should be stored at cold temperatures to prevent autolysis, which may be impeded by storage of trypsin at pH 3 or by using trypsin modified by reductive methylation.

When the pH is adjusted back to pH 8, activity returns. These human genes encode proteins with trypsin enzymatic activity: Other isoforms of trypsin may be found in other organisms. Activation of trypsin from proteolytic cleavage of trypsinogen in the pancreas can lead to a series of events that cause pancreatic self-digestion, resulting in pancreatitis. One consequence of the autosomal recessive disease cystic fibrosis is a deficiency in transport of trypsin and other digestive enzymes from the pancreas; this leads to the disorder termed meconium ileus, which involves intestinal obstruction due to overly thick meconium, broken down by trypsin and other proteases passed in feces. Trypsin is available in high quantity in pancreases, can be purified rather easily. Hence, it has been used in various biotechnological processes. In a tissue culture lab, trypsin is used to resuspend cells adherent to the cell culture dish wall during the process of harvesting cells; some cell types adhere to the sides and bottom of a dish.

Trypsin is used to cleave proteins holdi

Risurrezione

Risurrezione, is an opera or dramma in four acts by Franco Alfano. The libretto was written by Cesare Hanau based on the novel Resurrection by Leo Tolstoy; the first performance was given on 30 November 1904, in the Teatro Vittorio Emanuele, Italy. Place: Russia and Siberia Time: The end of 19th century Prince Dimitri arrives to say goodbye to his aunt, Sophia Ivanovna, before leaving for the war, his old playmate Katiusha, a young peasant girl, is now Sophia Ivanovna’s companion. Dimitri is overjoyed to meet her again and that night becomes her lover; the next day he leaves for the war. The station of a small town. Katiusha, now pregnant, has been driven out of the house, she anxiously waits for Prince Dimitri, due to pass through the station. But when she sees him arrive in the company of a prostitute, her courage fails her and she remains hidden until she goes away, pierced to her soul. Prison in St Petersburg. Katiusha, broken by Dimitri’s neglect of her and the death of her child, ends up in a place of debauchery.

She is involved in a crime and, although innocent, is condemned for murder during a difficult trial, is to be deported to Siberia. Before she leaves, now overcome with remorse, comes to see her in jail and offers to marry her, but she is in such a state of abject despair. On the road to Siberia. Katiusha has become herself again, the good sweet girl of former times, she has found the will to live by comforting her fellow deportees. Dimitri, who has followed her, now wants to marry her at any price, he obtains a pardon for her freedom. But Katiusha, although she still loves him with all her soul, refuses, she feels. Si, la ravviso la mia cara stanzaArioso of Dimitri Qualcun giù in giardino?... È Katiusha!.. – Duetto of Katerina and Dimitri Dio pietoso, fa ch’il venga alfin – Aria of Katerina Piangi, si, piangi – Arioso of Dimitri Quando la vidi, una voce mi disse – Aria of Simonson Ed ora, va... parti!... Son felice!!! – Finale duetto of Katerina and Dimitri 3 Flutes / 3 oboes / 3 clarinets / 2 bassoons / 1 contrabassoon 4 Horns / 3 trumpets / 3 trombones / 1 tuba Timpani / percussion / tubular bells / xylophone / celesta / 2 harps / piano Violins / violas / violoncellos / double basses Sources Amadeus Almanac, accessed 6 November 2008 Libretto of Risurrezione

International Covenant on Economic, Social and Cultural Rights

The International Covenant on Economic and Cultural Rights is a multilateral treaty adopted by the United Nations General Assembly on 16 December 1966 through GA. Resolution 2200A, came in force from 3 January 1976, it commits its parties to work toward the granting of economic and cultural rights to the Non-Self-Governing and Trust Territories and individuals, including labour rights and the right to health, the right to education, the right to an adequate standard of living. As of January 2020, the Covenant has 170 parties. A further four countries, including the United States, have signed but not ratified the Covenant; the ICESCR is part of the International Bill of Human Rights, along with the Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights, including the latter's first and second Optional Protocols. The Covenant is monitored by the UN Committee on Economic and Cultural Rights; the ICESCR has its roots in the same process. A "Declaration on the Essential Rights of Man" had been proposed at the 1945 San Francisco Conference which led to the founding of the United Nations, the Economic and Social Council was given the task of drafting it.

Early on in the process, the document was split into a declaration setting forth general principles of human rights, a convention or covenant containing binding commitments. The former evolved into the UDHR and was adopted on 10 December 1948. Drafting continued on the convention, but there remained significant differences between UN members on the relative importance of negative civil and political versus positive economic and cultural rights; these caused the convention to be split into two separate covenants, "one to contain civil and political rights and the other to contain economic and cultural rights." The two covenants were to contain as many similar provisions as possible, be opened for signature simultaneously. Each would contain an article on the right of all peoples to self-determination; the States Parties to the present Covenant, including those having responsibility for the administration of Non-Self-Governing and Trust Territories, shall promote the realisation of the right of self-determination, shall respect that right, in conformity with the provisions of the Charter of the United Nations.

The first document became the International Covenant on Civil and Political Rights, the second the International Covenant on Economic and Cultural Rights. The drafts were presented to the UN General Assembly for discussion in 1954, adopted in 1966; the Covenant follows the structure of the UDHR and the ICCPR, with a preamble and thirty-one articles, divided into five parts. Part 1 recognises the right of all peoples to self-determination, including the right to "freely determine their political status", pursue their economic and cultural goals, manage and dispose of their own resources, it recognises a negative right of a people not to be deprived of its means of subsistence, imposes an obligation on those parties still responsible for non-self governing and trust territories to encourage and respect their self-determination. Part 2 establishes the principle of "progressive realisation" It requires the rights be recognised "without discrimination of any kind as to race, sex, religion, political or other opinion, national or social origin, birth or other status".

The rights can only be limited by law, in a manner compatible with the nature of the rights, only for the purpose of "promoting the general welfare in a democratic society". Part 3 lists the rights themselves; these include rights to work, under "just and favourable conditions", with the right to form and join trade unions. This should be directed to "the full development of the human personality and the sense of its dignity", enable all persons to participate in society; as negative and positive rights are rights that oblige either action or inaction, many of these aforementioned rights include specific actions which must be undertaken to realise them, as they are positive economic and cultural rights that go beyond inaction-based civil and political negative rights. Part 4 governs reporting and monitoring of the Covenant and the steps taken by the parties to implement it, it allows the monitoring body – the United Nations Economic and Social Council – now the Committee on Economic and Cultural Rights – see below – to make general recommendations to the UN General Assembly on appropriate measures to realise the rights Part 5 governs ratification, entry into force, amendment of the Covenant.

Article 2 of the Covenant imposes a duty on all parties to take steps... to the maximum of its available resources, with a view to achieving progressively the full realization of the rights recognized in the present Covenant by all appropriate means, including the adopt