Other metabolic pathways Pentose phosphate pathway (phosphogluconate pathway) Produces NADPH and...
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Other metabolic pathways Pentose phosphate pathway (phosphogluconate pathway) Produces NADPH and ribose 5-phosphate Glc 6-phosphate + 2NADP + + H 2 O ribose 5-phos + CO 2 + 2NADPH + 2H + NADPH - used in fatty acid and cholesterol synthesis (found most in mammary gland, adrenal cortex, liver and adipose tissue) Ribose 5-phosphate - used to synthesize nucleic acids (occurs at high rates in growing and regenerating tissues and in tumors)
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Transcript of Other metabolic pathways Pentose phosphate pathway (phosphogluconate pathway) Produces NADPH and...
Other metabolic pathways
Pentose phosphate pathway (phosphogluconate pathway)Produces NADPH and ribose 5-phosphate
Glc 6-phosphate + 2NADP+ + H2O ribose 5-phos + CO2 + 2NADPH + 2H+
NADPH - used in fatty acid and cholesterol synthesis (found most in mammary gland, adrenal cortex, liver and adipose tissue)
Ribose 5-phosphate - used to synthesize nucleic acids (occurs at high rates in growing and regenerating tissues and in tumors)
Amino Acid Metabolism - BreakdownNeeded to produce amino groups because we cannot use N2 in air for most biological processes
Other metabolic pathways
Amino Acid Metabolism - Breakdown
Other metabolic pathways
Injested protein
Amino Acid Metabolism - Breakdown
Other metabolic pathways
Other metabolic pathways
Nitrogen Excretion & Urea Cycle Ammonia is toxic, if not used for synthesis of new AAs or other nitrogenous products - excreted! Ammonia deposited in mitochondria of hepatocytes is converted to urea in the urea cycle
Other metabolic pathwaysUrea Cycle - regulation1. By flux of nitrogen through cycle - depends on diet lots protein in diet = carbon skeletons used for fuel, lots of urea starvation = breakdown muscle protein for energy, lots of urea All enzymes (CPS-I and 4 in cycle) synthesized at higher rates in starving animals and animals on high protein diets
2. Carbomyl phosphate synthetase I allosterically activated by end product
Other metabolic pathwaysUrea Cycle - genetic defectsPatient cannot tolerate protein-rich diet, need small amounts of protein
Humans cannot live on a protein-free diet thoughWe are incapable of synthesizing half of the 20 AA, these are essential AAs that must be provided in diet
Bacteria & plants can synthesize all 20 AAs
must be provided in diet
Amino Acid Metabolism - Breakdown pathways
Other metabolic pathways
Amino Acid Metabolism - Breakdown pathwaysEnzyme cofactors are important to AA catabolism
Tetrahydrofolate - transfers 1-carbon units
Other metabolic pathways
S-Adenosylmethionine - transfers methyl groups
Amino Acid Metabolism - Breakdown pathways
Other metabolic pathways
Glucogenic AAs (red) - degraded to pyruvate, -ketoglutarate, succinyl-CoA, fumarate, oxaloacetateGo on to be converted into glc & glycogen
Ketogenic AAs (blue) - degraded to acetoacetyl-CoA, acetyl-CoAGo on to yield ketone bodies in liver
Some AAs are both - Trp, Phe, Tyr, Ile
Amino Acid Metabolism - Breakdown pathwaysGenetic defects affecting AA catabolism
Other metabolic pathways
Amino Acid Metabolism - Synthesis of all 20 AAs in bacteria or plants
Other metabolic pathways
Amino Acid Metabolism
Gly is a precursor of porphyrinsPorphyrins are part of heme, cytochromes
Gly, Met, Arg - synthesis of creatinecreatine = energy buffer in skeletal muscle
Gly, Glu, Cys - synthesis of glutathioneGlutathione = redox buffer
Tyr - synthesis of catecholamines (correlate with changes in BP)dopamine (Parkinson’s), epinephrine, norepinephrine
Glu - synthesis of neurotransmitterGABA (epilepsy)
His - synthesis of histaminevasodialator, allergic response, stimulates acid secretion in stomachTagamet is an antagonist of histamine
Met, Ornithine - synthesis of spermine (+4) & spermidine (+3)packaging of DNA
Other metabolic pathways
