BBMB 405 1st Edition Lecture 16 Outline of Last Lecture XV Chapter 23 Protein Turnover and Amino Acid Catabolism E Ammonium ion is converted into urea in most terrestrial vertebrates F Carbon atoms of degraded amino acids emerge as major metabolic intermediates Outline of Current Lecture XV Chapter 23 Protein Turnover and Amino Acid Catabolism F Carbon atoms of degraded amino acids emerge as major metabolic intermediates G Inborn errors of metabolism can disrupt amino acid degradation Current Lecture XV Chapter 23 Protein Turnover and Amino Acid Catabolism F Carbon atoms of degraded amino acids emerge as major metabolic intermediates con t 1 Amino acids produce carbon skeletons that make intermediates of TCA cycle 2 Emphasize catabolism of Ala Ser Gly Asp AspNH2 Glut GlutNH2 Meth 3 Non glucogenic amino acids leucine lysine phenylalanine tryptophan tyrosine 4 These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 5 Catabolism of amino acids Alanine serine glycine make pyruvate aspartate asparagine make oxyloacetate glutamate glutamine make alpha ketoglutarate methionine 6 Pyruvate as an entry point into metabolism for number of amino acids 7 Oxaloacetate as an entry point into metabolism for aspartate and asparagine 8 Alpha ketoglutarate as entry point into metabolism for five carbon amino acids a Glutamate dehydrogenase using NAD Glutamine via glutaminase glutamate via Alpha ketogluterate Transamination alpha keto acid to aa b c Do not memorize pathway of amino acids to glutamate 9 Succinyl coenzyme A is point of entry for several nonpolar amino acids 10 Methionine degradation requires formation of key methyl donor Sadenosylmethionine a Do memorize I think b Handout 2 18 asparagine is used to treat leukemia refer to this handout for alternate pathway for methionine catabolism SAM is a methyl donor SAH is one less carbon of SAM high concentrations of homocysteine in blood proves to increase risk for heart disease we can make our own cysteine but need methionine note I would memorize reaction on handout 11 The branched chain amino acids yield acetyl CoA acetoacetate or propionyl CoA a Muscle process branched chain amino acids liver is very poor at degradation of branched chain amino acids b Luecine is converted into acetyl CoA and acetoacetate it is not glucogenic because the end products are not glucogenic c d e f The degradative pathways of valine and isoleucine resemble that of leucine Biochemistry p 693 g Handout 2 18 Maple syrup disease autosomal recessive disease were L V I cannot be converted to Acyl CoA because alpha keto acid dehydrogenase is missing or defective alpha keto acid accumulateds and goes out in urine which now smells like maple syrup leads to severe neuro development problems cure feed minimum branch chain amino acids 12 Oxygenases are required for degradation of aromatic amino acids a b Can t make tyrosine unless have this reaction c d Reductant is tetrahydrobiopterin a derivative of biopterin e f g Homogentisate require O2 enzyme and if don t have it is excreted into urine When make contact with oxygen in air polymerize and turn black Disease called alcaptonuria h i Nearly all cleavages of aromatic rings in biological systems are catalyzed by dioxygenases Biochemistry p 695 j Handout 2 18 Phenylketonuria PKU is first genetic disorder that babies are tested for test concentration of phenylalanine feed phenylalanine if have disease assay for maple syrup disease G Inborn errors of metabolism can disrupt amino acid degradation a KIC from leucine degradation release CO2 and create HMB hydroxymethyl butyrate HMB leads to more muscle makes muscle grow more efficiently b Cystinuria cysteine in urine Error in transport of cysteine in kidney which leads to crystallization Autosomal recessive Have to drink water and eat less methionine c Handout 2 20 Rhizobium has nitrogenase which is sensitive to oxygen so rhizobium also has leghemoglobin which binds to oxygen and reaction can take place nitrogenase reaction convert nitrogen to ammonia
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