Functions of Amino Acids Synthesis of non essential amino acids Protein synthesis Buffer Neurotransmitter synthesis Energy Formation of Non Essential Amino Acids A Non essential aa s B Essential 9 1 we cannot synthesize them 2 must be consumed from diet C Conditionally Essential 1 Cys Tyr Protein Formation DNA I DNA RNA Proteins A Blueprint for all cells B Written in code C Genetic code is confined to nucleus D Only 10 of DNA is copied for RNA 1 remainder used to regulate transcription 2 promoter elements 1 2 Promoter elements a binding sites for transcription factors b hormone binding sites Exons coding regions Introns non coding regions mRNA is made from exons II RNA A mRNA messenger RNA 1 copy of the blueprint that can leave the nucleus B tRNA transfer RNA 1 reads the mRNA and binds to the corresponding amino acid C rRNA ribosomal RNA 1 protein synthesizing machinery 2 DNA RNA Proteins Proteins undergo post translational modifications including adding nutrients to become active proteins I Primary Structure a Sequencing of amino acids in polypeptide chain III Secondary structure Folding of primary structure a helix b pleated sheet IV Tertiary Structure a Looping and binding of aa s located at considerable distance apart on 2 structure V Quaternary Structure a Involves two or more polypeptide chains 3 VI Functional Categories of proteins a Enzymes all enzymes are proteins b Hormones derived from 1 or more a a ex insulin 2 polypeptide chains disulfide bridge c Structural Proteins 1 contractile proteins muscle 2 fibrous proteins collagen d Cell Membrane Proteins embedded in cell membrane 1 membrane channels transporters 2 Receptors a LDL receptors 4 e Plasma Proteins 1 Albumin Vein Interstitial space albumin pressure 26 pressure 17 a synthesized in liver and released into blood b Transports nutrients B6 Zn Ca fatty acids VII Mutations A Alterations or changes in the genetic code usually associated with a disease 1 2 Gene rearrangements 3 Frame shift mutations 4 Gene deletions 5 Duplications B Some Nutrient Related Mutations 1 Cystic Fibrosis 2 Wilson s Disease 3 Acrodermatitis Enteropathica 4 Hemochromatosis 5 Vitamin D Resistant Rickets 5 Cystic Fibrosis Defective gene and its protein product Body produces unusually thick sticky mucus Lungs and Pancreas Vitamin D Resistant Rickets Genetic Mutation in the VDR alter the function of the receptor Vitamin D Resistant Rickets Genetic Mutation in the VDR alter the function of the receptor C Polymorphisms 1 Changes usually not disease related 2 Responsible for individual differences 6 Functions of Amino Acids Synthesis of non essential amino acids Protein synthesis Neurotransmitter synthesis Buffer Energy I Amino Acid Metabolism A Decarboxylation B Side Chain Cleavage C Deamination D Transamination H3N COO CH R A Decarboxylation 1 removal of carboxyl group 2 Neurotransmitter synthesis a Tyrosine b Glutamate c Tryptophan 7 B Side Chain Cleavage 1 removal of R chain C Deamination amino acid keto acid NH3 8 D Transamination 1 formation of non essential amino acids 2 catalyzed by aminotransferase enzymes Transferases as an indicator of liver function Alanine amino transferase ALT Aspartate amino transferase AST 9 II Metabolism of keto acids A keto acid carbon skeleton left after N group has been removed B Can be used for production of 1 energy C Glucogenic vs Ketogenic 1 Glucogenic conveted to pyruvate and krebs intermediates 2 Ketogenic converted to acetyl CoA and acetoacetone 3 Glucogenic and Ketogenic 10 D A brief intro to Nitrogen a Protein turnover b Nitrogen balance 1 intake vs output 2 indicator of body protein 3 Nitrogen balance studies Nitrogen Balance 1g Pro 0 16g Nitrogen 1 Positive Nitrogen Balance 2 Negative Nitrogen Balance 3 Equal Balance 11 III Disposal of Ammonia Urea Synthesis A Nitrogen Excretion 1 2500 kcal day intake 300 g CHO 100 g fat 100 g pro 2 B Regulation 1 CPS I carbamoyl phospate synthetase I a rate limiting enzyme b forms monomer or dimer c monomer is active d Allosterically regulated by Regulation continued 2 High Protein Diet a increased urea cycling b 12 3 Carbamoyl Phosphate Synthetase deficiency a rare 1 62 000 b neonatal hyperammonemia 1 vomiting 2 irritability 3 intermittent ataxia 4 lethargy 5 mental retardation IV Organ Specific Metabolism of Amino Acids A Liver 1 amino acids are transported to liver via hepatic portal system 2 from liver transported to other tissues 5 Liver specific enzymes a AST ALT indicators of liver fxn b Arginase urea cycle c Phenylalanine Hydroxylase 13 2 tyrosine used for a melanin b neurotransmitter synthesis 3 Phenylketonuria a deficiency of enzyme b symptoms untreated infants are irritable and have an eczema type rash as they get older without treatment c All infants are tested at 3 days d low phenylalanine diet liver enzymes cont d Methionine Adenosyl Transferase methionine S adenosyl methionine SAM 1 Norepinephrine Epinephrine 14 B Muscle 1 Branched chain amino acid metabolism a Valine b Leucine c Isoleucine 2 BCAA transferase a High activity in skeletal muscle 3 Once transaminated the keto acids a Remain in muscle BCAA transferase BCAA N keto acid BCKD 4 BCKD complex branched chain keto dehydrogenase a Complex made up of subunits that carry out a series of dehydrogenase reactions 15 C Muscle and Liver 1 Glucose Alanine Cycle 2 Purpose D Kidney 1 Secondary site of gluconeogenesis 2 Excretion of nitrogenous waste 3 Deamination 16 Glutamine deamination glutamate NH3 NH3 H ammonium E Brain 1 Neurotransmitter synthesis a Glutamate GABA b Tyrosine dopamine norepinephrine epinephrine c Tryptophan serotonin 2 Glutamate removal of ammonia from brain 3 Glucose Synthesis Proteins Other 17 I Prions proteinaceous infectious particles which are resistant to inactivation by most procedures that modify nucleic acids A convert normal proteins into prions B folding C Diseases caused by prions 1 Creuzfeldt Jacob 2 Scrapie 3 Mad Cow II Glutathione A tripepetide made of glycine cysteine glutamate B functions III Carnitine A lysine SAM carnitine 18 IV Creatine A can be synthesized in body or obtained from foods meat and fish D Phosphocreatine 1 storehouse for high energy phosphate 2 Rapidly contracting muscle needs ATP 4 Does not stay in muscle for extended period of time a b excreted by kidneys c urinary creatinine 1 indicator of 2 indicator of 19 V Purine and Pyrmidine Bases A Pyrmidines uracil cytosine thymine B Purines adenine and guanine 20
View Full Document
Unlocking...