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metabolism of nucleotide and nucleic acid - Coggle Diagram
metabolism of nucleotide and nucleic acid
Nucleotide Biosynthesis
De Novo Biosynthesis of Nucleotides
Glu provides most amino groups
Gly is precursor for purines
salvaged from RNA, DNA, and
cofactor degradation.
Asp is precursor for pyrimidines
De Novo Biosynthesis of Purines
begin wIth PRPP
inosinate (IMP) 中間產物
Synthesis of AMP and GMP from IMP
in E.coli
Feedback Inhibition
De Novo Biosynthesis of Pyrimidine Nucleotides
by first making the pyrimidine
ring
orotidylate is decarboxylated (CO2 relaese)
Asp
convert (UTP +amino acid) to CTP
other
Ribonucleotides Are Precursors to
Deoxyribonucleotides
by Ribonucleotide Reductase
Has Two
Types of Regulatory Sites
NADPH serves as the electron
donor
Regulation of Ribonucleotide
Reductase by dNTPs
dTMP Is Made from dUTP
by Thymidylate Synthase
Folic Acid Deficiency Leads to
Reduced Thymidylate Synthesis
Catabolism nucleotide
Purines
Deamination and hydrolysis
xanthine
Dephosphorylation
uric acid
Excess Uric Acid Seen in Gout
Pyrimidines
NH4+ & Urea
others
Purine and Pyrimidine Bases Are
Recycled by Salvage Pathways
The brain is especially dependent
The lack of hypoxanthine-guanine phosphoribosyltransferase leads to Lesch-Nyhan syndrome
Many Chemotherapeutic Agents
Target Nucleotide Biosynthesis
Metabolism of Amino acids
Dietary Proteins Are Hydrolyzed into Amino Acids
Trypsin and chymotrypsin( in the small intestine)
• Aminopeptidase and carboxypeptidases A and B(in the small intestine)
degrade peptides into amino acids
• Pepsin 胃蛋白酶
Amino Acid Catabolism
Removal of the Amino Group(transamination)
Enzymatic Transamination
Uses the pyridoxal phosphate (PLP) cofactor
-ketoglutarate
• L-Glutamine
Enzymatic Transamination to Glutamate
Ammonia Is Safely Transported in the
Bloodstream as Glutamine
Ammonia Collected in Glutamate Is
Removed by Glutamate Dehydrogenase
mitochondrial matrix
Excess Glutamate Is Metabolized in the
Mitochondria of Hepatocytes
Urea Cycle
within the cytosol.
Entry of Aspartate其 中一種方式
Aspartate–Arginosuccinate Shunt Links
Urea Cycle and Citric Acid Cycle
Degradation of Branched-Chain
Amino Acids Does Not Occur in the Liver
Cofactors
adoMet
methyl transfer
biotin
THF
transfer 1-carbon
The Nitrogen Cycle
Nitrification
Assimilation
Fixation
Denitrification
amino acid synthesis
Ammonia Is Incorporated into
Biomolecules Through Glu and Gln
Proline and Arginine Derive from Glutamate
Arginine Is Synthesized from
Ornithine in Animals
Serine Derives from 3-Phosphoglycerateof Glycolysis
Oxidation
transamination
dephosphorylation
Biosynthesis of Cys from Homocysteine
and Ser in Mammals
Oxaloacetate Yields Asp, Which Yields
Asn, Met, Lys, and Thr
regulation
feedback inhibition
Thr
isozymes for regulation
Important Metabolites Are Derived
From Amino Acids
Glutathione
from Glu, Cys, and Gly
Neurotransmitters and signaling molecules
Phosphocreatine
Gly and Arg Are Precursors
Cell-wall constituents
Porphyrin rings (e.g., heme)
Glycine or Glutamate Is the Precursor to Porphyrins( makes up the heme of hemoglobin)
Heme Is the Source of Bile Pigments
Biliverdin reductase , bilirubin, a yellow compound, major pigment of urine
Heme oxygenase , biliverdin, a green compound