BICH 411 1st Edition Lecture 20Outline of Last Lecture I. Nitrogen MetabolismII. Nitrate AssimilationIII. Nitrogen FixationIV. Ammonium ion assimilationV. Making amino acidsOutline of Current Lecture I. Amino acid formationII. Amino acid inhibitor herbicidesIII. Amino acid catabolismIV. Inborn Errors of MetabolismCurrent LectureAmino acid formation**for this test be sure to focus on which carbon backbone is the source**-The aspartate family – Asp formed from oxaloacetate (4 carbon backbone)-Asn, Thr, Met, and Lys can be made from Asp-don’t need to know the mechanism-Asparagine is important for normal and cancerous lymphocytes, so asparaginase is antreatment for leukemia in kids – can inhibit asparagine synthetase-figure 25.27 shows the reactions – note that forming Threonine is expensive!-the sulfur in Methionine comes from Cysteine-The pyruvate family (3 carbon backbone)-Val, Leu, Ala, Ile are formed from pyruvate -alanine formation is the easiest – it’s pyruvate transamination-Leucine begins with alpha-ketoglutarate, involves an intermediate of valine formation-The 3-phosphoglycerate family (3 carbon backbone)-3-Phosphoglycerate dehydrogenase brings it from glycolysis-Ser, Gly, and Cys are formed-Serine is the easiest to make – transamination of glucose, and a phosphatase-Serine hydroxymethylase transfers a beta-carbon to THF for glycine formation-Cysteine needs a pyroxidal phosphate (PLP)-dependent enzymeThese 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.Amino acid inhibitor Herbicides-some herbicides use inhibitors of enzymes that produce essential amino acids – since animals can’t make those amino acids, they lack the enzymes. Thus they don’t affect animals. “Round Up” is an example of this type of herbicide. (usually Phe, Val, Leu, Ile)**This would be a good exam question**Amino acid catabolism**Know which amino acids are ketogenic (make ketones, like acetate), glucogenic (metabolite can go through gluconeogenesis), or both – good test questions**-Leu and Lys are the only that are purely ketogenic!!***Figure 25.41 is important! Know for quiz!!-When Ala, Ser, Cys, Gly, Trp, or Thr are broken down into pyruvate, that pyruvate can enter theTCA cycle-Arg, Pro, and His (5 carbon backbone) can be catabolized to glutamate, which can be further changed to an alpha-ketoglutarate. (Arginine releases a Urea in the process)-Valine, Methionine, and Isoleucine can be broken down to Propionyl-CoA. This can further be broken down with an ATP and carboxylase to form Succinyl-CoA. Succinyl-CoA can enter the TCAcycle.-Leucine (purely ketogenic) can be broken down into acetoacetate and acetyl-CoA. -The branched amino acids (Val, Leu, Ile) are degraded in the liver, muscle, and adipose tissue – all use the same first 3 reactions:-transamination-oxidative decarboxylation-dehydrogenationInborn Errors of Metabolism-Maple Syrup Urine Disease – defect in metabolism of branched amino acids – buildup of ketoacids (concentrated in urine and earwax)-urine smells like maple syrup-now tested for on newborns-This one’s the worst of the 3 we discuss-Phe and Tyr (aromatic) are catabolized to form acetoacetate and fumarate (TCA and Urea cycle)-Alkaptonuria and phenylketonuria are genetic – result from defective Phe catabolism-alkaptonuria sufferers have dark urine (this is the least severe of the 3)-phenylketonurics suffer mental retardation if they consume phenylalanine as whiledeveloping, not as much of a problem when