Amino Acids 2024-2025 PDF

 CHAPTERS GENERAL BIOCHEMISTRY SPECIAL BIOCHEMISTRY ▪ Structure of the cell ▪ Genetic biochemistry ▪ Amino acids, peptides, proteins▪ Biochemistry of endocrine glands ▪ Nucleic acids ▪ Neurotransmitters ▪ Enzymes, coenzymes, vit...

 CHAPTERS GENERAL BIOCHEMISTRY SPECIAL BIOCHEMISTRY ▪ Structure of the cell ▪ Genetic biochemistry ▪ Amino acids, peptides, proteins▪ Biochemistry of endocrine glands ▪ Nucleic acids ▪ Neurotransmitters ▪ Enzymes, coenzymes, vitamins ▪ Biochemistry of the bone system ▪ Central metabolic pathways ▪ Biochemistry of muscular contr. ▪ Carbohydrates – metabolism ▪ Haemostasis, fibrinolysis ▪ Lipids - metabolism ▪ Heme metabolism ▪ Amino acid metabolism ▪ Nucleotide metabolism  The importance of Biochemistry ▪ Studies various body processes and physiology of biomolecules ▪ Biochemistry is used in clinical diagnosis ▪ Diet and nutrition ▪ Forensic medicine ▪ Manufacture of several biological products ▪ Treatment of diseases ▪ 1. Membrane protein 4 – Lysosome 7 - Mitochondrion ▪ 2. Double phospholipid layer 5 – Peroxisome 8 – Rough ▪ 3. Golgi system 6 – Nucleus endoplasmic reticulum  BIOMOLECULES ▪ Proteins: amino acids ▪ Nucleic acids: nucleobases + glucids + phosphate groups ▪ Carbohydrates: monosaccharydes – polysaccharydes ▪ Lipids: triglycerids and phospholipids (contain fatty acid side chains), cholesterol, etc. Amino acids Amino acids Valences of atoms, basic groups AMINO ACIDS  Definition and classification of amino acids ▪ Definition: Amino acids are organic compounds containing two functional groups: a carboxyl (-COOH) and an amino (-NH2) group, bond to the same carbon, called Cα. ▪ There is a huge number of amino acids in nature, but only 20 are genetically codified (classic), which are present in the structure of the proteins in the human body.  Amino acids ▪ 20 (+ 2) standard (genetically codified) two, selenocysteine and pyrrolysine (not in eukaryotes) ▪ The 21st and 22nd amino acids are specified by the stop codons UGA and UAG respectively, modified with downstream stem-loop structures in the mRNA. - Nonpolar amino acids - Polar amino acids (charged and uncharged) ▪ Non-standard: - non-proteinogenic - proteinogenic ▪ Essential ▪ Semiessential ▪ Non essential  NON ESSENTIAL AMINO ACIDS ✓ amino acids which can be produced in the body in enough amounts to cover the necessities ESSENTIAL AMINO ACIDS ✓ amino acids which cannot be produced in the body, so we need to get them from food SEMIESSENTIAL AMINO ACIDS ✓ amino acids which can be produced by the body, but in childhood, during the growing period, additional amounts are necessary from food GENETICALLY CODIFIED AMINO ACIDS Amino acids with nonpolar (hydrophobic) side chain Structure of amino acids with non-polar side chains  Amino acids with non-polar side chains ▪ Glycine: is the smallest standard amino acid, frequent in the collagen’s structure, involved in the formation of primary bile acids and purine nucleobases, in heme biosynthesis ▪ Alanine: all standard amino acids (except proline) are alanine derivatives, can be transformed to pyruvate by transamination ▪ Valine, leucine, isoleucine: ess., branched-chain amino acids ▪ Proline: cyclic, causing deviation of the polypeptide chain ▪ Methionine: important source of sulfur, a methyl group donor included in the structure of SAM (S-adenosyl-methionine) ▪ Phenylalanine: main source of aromatic rings in the body. ▪ Tryptophan: precursor of serotonin, vitamin PP, melatonin  Methionine (Met) ▪ Essential amino acid ▪ Methyl group donor (ex.: noradrenaline is transformed to adrenaline by methylation, involving SAM, transformed into SAHC) Met GENETICALLY CODIFIED AMINO ACIDS Amino acids with polar (hydrophylic) side chain Structure of amino acids with polar side chains and electric charge at pH = 7.4  Amino acids with polar, charged side chains ▪ Aspartic acid: is an excitatory neurotransmitter, has role in the urea cycle, the synthesis of nucleobases ▪ Glutamic acid: is an excitatory neurotransmitter, has role in transaminations ▪ Histidine: is in the composition of hemoglobin (buffer) ▪ Lysine: having a long chain, helps to link enzymes to coenzymes ▪ Arginine: is involved in the urea cycle, it is a precursor for the synthesis of NO Structure of amino acids with polar side chains and no electric charge at pH = 7.4 Amino acids with polar, uncharged side chains ▪ Serine: is in the active site of serine protease enzymes, can connect the glucid and proteic component in glycoproteins ▪ Threonine: can connect the glucid and proteic component in glycoproteins ▪ Cysteine: is in the composition of glutathione ▪ Tyrosine: it is formed by the hydroxylation of phenylalanine, it is the precursor of melanine ▪ Asparagine: is a transport form of amoniac, can be derived from aspartic acid ▪ Glutamine: is a transport form of amoniac, can be derived from glutamic acid  Classification of standard amino acids ▪ Essential: valine, leucine, isoleucine, lysine, methionine, phenylalanine, tryptophan, and threonine ▪ Semiessential: arginine and histidine ▪ Non essential: the rest ▪ Ketogenic: lysine, leucine ▪ Mixed chain (keto-and glucogenic): tyrosine, phenylalanine, tryptophan, isoleucine ▪ Glucogenic: the rest Structure of non-standard amino acids present in the structure of proteins (Gla) 4-OH-Pro, 5-OH-Lys are present in the structure of collagen fibers 5-Hydroxylysine Gla is present in the vitamin K- dependent coagulation factors Structure of non-standard amino acids not present in the structure of proteins (accumulated increases the risk of thrombosis) (involved in the urea cycle) (in CoA-SH) PABA (in folate) (inhibitory neurotransmitter)  Beta-alanine ▪ It is present in the structure Coenzyme A of pantothenic acid, in coenzyme A – an acyl transporter COO- + H C CH2 NH3 H  PABA (para amino benzoic acid) ▪ It is present in the structure of folic acid (vitamin B9) Pteridine Glutamic ring PABA acid Folic acid