BIO-310
BIOCHEMISTRY II
IX. WEEK
LECTURE CONTENTS OF 9TH WEEK
• Overview of Amino Acid Catabolism:
• In animals, amino acids in 3 different metabolic conditions undergo oxidative degradation;
https://www.google.com/url?sa=i&url=http%3A%2F%2Fpressbooks-dev.oer.hawaii.edu%2Fhumannutrition
%2Fchapter%2Fprotein-digestion-and-absorption%2F&psig=AOvVaw2PTo_QCJja4-
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https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.biologydiscussion.com%2Fproteins%2Fmetabolism- proteins%2Fprotein-digestion-and-absorption-process-protein-metabolism%2F17210&psig=AOvVaw2PTo_QCJja4- Z1nteSIr6X&ust=1589321075324000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCICqp8XorOkCFQAAAAAdA AAAABAU
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.quora.com%2FHow-does-digestion-of-proteins-take- place&psig=AOvVaw2PTo_QCJja4-
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• 1-Some amino acids that are released by protein degradation during normal synthesis and degradation of cellular proteins and not used for new protein synthesis undergo oxidative degradation.
• 2-After a protein-rich diet, the digested amino acids are destroyed if the body needs more than for protein synthesis; amino acids cannot be stored.
• 3-In the case of fasting or untreated diabetes, that is, carbohydrates are not sufficient or are not used properly, cellular proteins are used as fuel.
• The digestion of proteins stimulates the secretion of HCl and pepsinogen from parietal cells by the release of gastrin hormone in the stomach.
• The acidic medium facilitates the enzymatic hydrolysis of peptide bonds by disrupting the three-dimensional structure of both the antiseptic and the spherical proteins.
• Pepsinogen is activated at low pH to
hydrolyze from the amino end of Phe, Trp and Try amino acids.
• The acidic gastric contents secrete the
secretin hormone into the blood, allowing the release of bicarbonate to neutralize the
gastric HCl of the pancreas.
• The amino acids in the small intestine cause the release of cholecytokine hormone into the blood, releasing the zymogens of pancreatic enzymes, trypsin, chymotrypsin and carboxypeptidase A and B.
• Thus, small peptides and structures transformed into amino acids are absorbed by the small intestinal mucosa and transported to the liver through the lymphatic system and capillaries.
https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.bioinfo.org.cn%2Fbook%2Fbiochemistry
%2Fchapt17%2Fbio1.htm&psig=AOvVaw13pXsc2QrQ7qD6Ac2CeO6u&ust=1589145167641000&source=images&cd=vfe&v ed=0CAIQjRxqFwoTCNC68aXZp-kCFQAAAAAdAAAAABBN
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.slideserve.com%2Fskylar%2Fbiochemistry-482- amino-acid-
metabolism&psig=AOvVaw13pXsc2QrQ7qD6Ac2CeO6u&ust=1589145167641000&source=images&cd=vfe&v ed=0CAIQjRxqFwoTCNC68aXZp-kCFQAAAAAdAAAAABBi
• The amino acids that come into the liver are transferred to the α-amine groups, α- ketoglutarate, by the transaminase or amino transferase enzymes to form glutamate. There are different transaminases;
• ALT (GPT)
• AST (GOT)
•DETAILED INFORMATION ON THIS SUBJECT WILL BE DISCUSSED
WITH BIOCHEMICAL FORMULAS
REFERENCES
MAIN : LEHNINGER PRINCIPLES OF BIOCHEMISTRY, DAVID L. NELSON, MICHAEL M.
COX, 5TH EDITION, 2013.
PRİNCİPLES OF BİOCHEMİSTRY, H. R. HORTON, L.
A. MORAN, K. G. SCRİMGEOUR, M. D. PERRY, J.
D. RAWN, PEARSON PRENTİS HALL, 2006.
COLOR ATLAS OF BIOCHEMISTRY, J. KOOLMAN, K. H. ROEHM, GEORG THIEME VERLAG, 2005.
HARPER’S ILLUSTRATED BIOCHEMISTRY, R. K.
MURRAY, D. K. GRANNER, P. A. MAYES, V. W.
RODWELL, LANGE MEDICAL BOOKS/MCGRAW- HILL MEDİCAL PUBLISHING DIVISION, 2003.
BASİC CONCEPTS İN BİOCHEMİSTRY, A STUDENT’S SURVİVAL GUİDE, H. F. GİLBERT, MCGRAW-HİLL HEALTH PROFFESİONS DİVİSİON, 2000.
