Far Eastern University
Institute of Arts and Sciences
Regulatory Proteins: Hormones Reviewer
Group 1 – MT13215
Santos, Catheleyn (Angiotensin II Hormone)
Gutierrez, Junyl (Vasopressin)
Bartolome, Relyn Joy (Oxytocin)
Flores, Bea Steffi (Glucagon)
Montenegro, Charles John (Insulin)
Santuyo, Lara Mae (Amylin)
Lamorena, Earl John (Gastrin and Cholesystokinin)
Mr. Rogelio Grafilo
January 21, 2015
ANGIOTENSIN II HORMONE
Where did Angiotensin II Hormone come from?
Angiotensinogen - a renin substrate; released by the liver (hepatocytes), the most important amino acids are the first 12 amino acids; other parts of the substrate has no further biological activity. (prohormone in Angiotensin II Hormone) Renin - (an enzyme-acting hormone) contains 340 amino acids from the kidneys. When combined, the Renin catalyzes the Angiotensinogen into a 10-amino acid, Angiotensin I. Angiotensin I - has no biological activity, only a precursor to angiotensin II. Angiotensin Converting Enzyme (ACE) – removes two amino acids at the C-terminal of the Angiotensin I; found in the lungs and the vascular endothelium. When combined, the ACE catalyzes the Angiotensin I to produce an 8-amino acid, Angiotensin II. In conclusion, is called the Renin-Angiotensin Pathway:
Angiotensin II Hormone - has a molecular formula of C50H71N13O12. It constricts the walls of arterioles closing down capillary beds, stimulates the adrenal cortex to release aldosterone. Aldosterone (a steroid hormone from adrenal glands) causes the kidneys to reclaim more Na and water ions, increases the strength of the heartbeat, stimulates the pituitary to release the antidiuretic hormone (ADH, also known as vasopressin). These factors contribute to the increase in blood pressure.
Asparagine, a polar positive chain; exhibits ionic bond.
Arginine, a polar positive chain; exhibits ionic bond.
Valine, a non-polar alipathic chain; exhibits hydrophobic interaction. Tyrosine, aromatic and heterocyclic chain; exhibits stacking interaction. Isoleucine, a non-polar alipathic chain; exhibits hydrophobic interaction. Histidine, a non-aromatic and a heterocyclic chain; exhibits stacking interaction. Proline, a non-aromatic and a heterocyclic chain; exhibits stacking interaction. Phenylalanine, a non-polar, aromatic and a heterocyclic chain; exhibits stacking interaction.
The most important amino acids present in Angiotensin II are: tyrosine and phenylalanine. Any alterations or deletion within these two amino acids can cause the complete inactivation of the Angiotensin II Hormone.
Where does it bind?
Angiotensin II is a potent vasoconstrictor that constricts both arteries and veins to increase blood pressure by binding on AT-1 receptor (prominent in adults) and AT-2 receptor (prominent in fetus) which also inactivates Nitric Oxide that causes vasoconstriction.
What are the other types of Angiotensin?
Angiotensin II is further catalysed into Angiotensin III by the Angiotensineases present in the capillaries which acts as 40% pressor and 100% aldosterone stimulator. Angiotensin IV came from Angiotensin III also catalysed by the action of Angiotensineases, is the newly discovered kind of angiotensin, its function is currently on debate, but it is believed it enhances glucagon uptake. VASOPRESSIN HORMONE
Prohormone in neural cells of hypothalamus and matures as they pass down axons with carrier proteins called neurophysins. Is composed of 164 amino acids before it is activated by a cleavage. Is a peptide hormone composed of 9 amino acids including arginine at its 8th position. Arginine is important in the binding affinity and once deleted, it can cause inability to concentrate urine. Urine is concentrated by increasing the kidney reabsorption rate of tubule cells. If the urine is not concentrated, it will lead to mutations such as nephrogenic diabetes insipidus and hypernathemia....
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