Biochemistry of Urine and Amino Acids

Glutaminase = Removes nitrogen and generates glutamate Asparaginase = Breaks down asparagine L Amino Acid Oxidase = Generates peroxide from L amino acids D Amino Acid Oxidase = Breaks down D amino acids and generates peroxide

Glucose-Alanine Cycle = Converts alanine to pyruvate Urea Cycle = Converts ammonia to urea Ammonia trapping in urine = Decreases toxicity by forming ammonium ion Catalase action = Detoxifies peroxide in peroxisomes

Ammonia = Toxic at levels greater than 10 micrograms per liter Ammonium ion = Toxic at levels around half a milligram Urea = Less toxic compared to ammonia Glutamate = Non-toxic nitrogen carrier

<p>Alanine = Converted to pyruvate Pyruvate = Converted back to glucose in the liver Glucose = Used in brain and red blood cells Muscle cells = Prevented from using glucose for fatty acid breakdown</p> Signup and view all the answers

<p>Complete block in the urea cycle = Incompatible with life High concentration of ammonium ion = 100-fold higher than ammonia under physiological conditions Toxic ammonia levels = Dangerous to cellular function Catalase deficiency = Increased peroxide toxicity</p> Signup and view all the answers

<p>CPS 1 = Ammonium ion + Bicarbonate → Carbamyl phosphate Ornithine Transcarbamylase = Citrulline → Argininosuccinate Argininosuccinate Synthetase = Citrulline + Aspartate → Arginosuccinate Arginase = Arginine → Urea</p> Signup and view all the answers

<p>Bicarbonate + Ammonium ion = Carbamyl phosphate Citrulline + Aspartate = Arginosuccinate Arginosuccinate = Arginine Arginine = Urea</p> Signup and view all the answers

<p>Hyperammonemia = High levels of ammonia in blood N-Acetylglutamate = Activates CPS 1 CPS 1 = Rate-limiting enzyme Urea precursors = Provide nitrogen for the urea cycle</p> Signup and view all the answers

<p>Aspartate = Urea precursor Carbamyl phosphate = Intermediate in urea cycle Free ammonium ion = Nitrogen donor Citrulline = Precursor to arginine</p> Signup and view all the answers

<p>Step 1 = CPS 1 Step 2 = Ornithine Transcarbamylase Step 3 = Argininosuccinate Synthetase Step 4 = Argininosuccinate Lyase</p> Signup and view all the answers

<p>CPS 1 = Bicarbonate, Ammonium ion Ornithine Transcarbamylase = Ornithine, Carbamyl phosphate Argininosuccinate Synthetase = Citrulline, Aspartate Arginase = Arginine</p> Signup and view all the answers

<p>CPS 1 = Activated by N-Acetylglutamate Ornithine Transcarbamylase = Driven by flow of nitrogen Argininosuccinate Synthetase = Sensitive to citrulline levels Arginase = Influenced by arginine concentration</p> Signup and view all the answers

<p>Hyperammonemia = Leads to ammonia intoxication Urea Cycle Defects = Inability to convert ammonia to urea Intolerant to protein = Shows mental and CNS deficiencies Low protein diet = Primary treatment for hyperammonemia</p> Signup and view all the answers

<p>Carbamylphosphate synthetase = Converts free ammonium to a compound for TCA cycle Ornithine transcarbamylase = Forms citrulline from ornithine and carbamyl phosphate N Acetylglutamate = Important compound in regulation of urea cycle Alpha Keto Glutarate = Transaminates nitrogen to form glutamate</p> Signup and view all the answers

<p>Alpha Keto Glutarate = Forms glutamate as intracellular nitrogen carrier Low protein diet = Reduces ammonia production Ammonia accumulation = Causes neurocognitive impairments Urea formation = Converts toxic ammonia for excretion</p> Signup and view all the answers

<p>Mitochondrial matrix = Location of the first two urea cycle enzymes Cytosol = Location of the remaining three urea cycle enzymes Liver = Primary organ for urea cycle TCA cycle = Metabolic cycle linked to urea production</p> Signup and view all the answers

<p>Citrulline = Product of ornithine and carbamyl phosphate Carbamyl phosphate = Activated form of urea for entry into TCA cycle Free ammonium = Starting substrate for urea cycle Glutamate = Intracellular nitrogen carrier formed by transamination</p> Signup and view all the answers

<p>Alpha Keto Glutarate = Helps detoxify ammonia Low protein diet = Minimizes nitrogen intake Supplementation with N Acetylglutamate = Enhanced urea cycle efficiency Avoidance of protein ingestion = Prevents acute hyperammonemic episodes</p> Signup and view all the answers

<p>Mental deficiencies = Cognitive impairments due to ammonia buildup CNS deficiencies = Neurological issues from elevated ammonia Protein intolerance = Dietary limitation resulting from ammonia toxicity Hyperammonemia symptoms = Indicates need for immediate treatment</p> Signup and view all the answers

<p>Ammonium ion = Starting compound for urea cycle Bicarbonate = Combines with ammonium in CPS 1 reaction Nicotinamide adenine dinucleotide (NAD) = Aids in redox reactions, indirectly linked Glutamine = Ammonia transporter in the brain</p> Signup and view all the answers