Cysteine and methionine metabolism - Homo sapiens (human)

Curator(s): Joe Strothman

Cysteine and methionine are sulfur-containing amino acids. Cysteine is synthesized from serine through different pathways in different organism groups. In bacteria and plants, cysteine is converted from serine (via acetylserine) by transfer of hydrogen sulfide. In animals, methionine-derived homocysteine is used as sulfur source and its condensation product with serine (cystathionine) is converted to cysteine. Cysteine is metabolized to pyruvate in multiple routes. Methionine is an essential amino acid, which animals cannot synthesize. In bacteria and plants, methionine is synthesized from aspartate. S-Adenosylmethionine (SAM), synthesized from methionine and ATP, is a methyl group donor in many important transfer reactions including DNA methylation for regulation of gene expression. SAM may also be used to regenerate methionine in the methionine salvage pathway.    
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Cysteine and methionine metabolism - Homo sapiens (human) cluster_node114 !meth node1 L-Serine node3 node1->node3 node69 node1->node69 node2 node2->node1 node5 O-Acetyl -L-serine node2->node5 node4 2-Aminoacrylate node3->node4 node20 L-Cysteate node4->node20 node6 node5->node6 node7 node5->node7 node8 node5->node8 node9 S-Sulfo -L-cysteine node6->node9 node15 L-Cysteine node6->node15 node7->node15 Homocysteine node7->Homocysteine node8->node15 Sulfide Sulfide->node6 Sulfide->node8 node10 node10->node9 node16 L-Cystine node10->node16 Sulfate node10->Sulfate Glutathione node10->Glutathione node18 S-Glutathionyl -L-cysteine node10->node18 node11 node11->node15 node12 node12->node15 node12->node16 node13 node13->node15 node13->Glutathione node13->node18 node14 node14->node20 node15->node14 node33 node15->node33 node34 node15->node34 Glutathione metabolism node15->Glutathione metabolism Pantothenate and CoA biosynthesis node15->Pantothenate and CoA biosynthesis node16->node11 node30 node16->node30 node31 node16->node31 Thiocysteine node17 16 Glutathione->node17 Glutathione node19 O-Phospho -L-serine node19->node8 Taurine and hypotaurine metabolism node20->Taurine and hypotaurine metabolism node29 node20->node29 node21 node21->node15 node21->node20 node22 3-Sulfo -pyruvate node21->node22 node39 3-Mercapto -pyruvate node21->node39 node42 3-Sulfino -pyruvate node21->node42 node23 node23->node22 node24 3-Sulfo -acetate node23->node24 node25 node24->node25 Bisulfite node25->Bisulfite Pyruvate node25->Pyruvate node26 2 Pyruvate->node26 Pyruvate node27 Pyruvate metabolism - Homo sapiens Pyruvate->node27 node28 Glycine, serine and threonine metabolism node28->node1 Propanoate metabolism node29->Bisulfite node29->Pyruvate node30->node15 node30->Thiocysteine node30->Pyruvate node30->Homocysteine node31->node15 node31->Thiocysteine node31->Pyruvate node47 2-Oxobutanoate node31->node47 node53 L-Cystathionine node31->node53 node32 node32->node15 node32->node39 node38 D-Cysteine node33->node38 node43 L-Cysteine -sulfinate node34->node43 node35 node40 3-Mercaptolactate node35->node40 node36 node36->Pyruvate node37 node37->Pyruvate node41 Thio-sulfate node37->node41 node38->node36 node39->node35 node39->node37 Sulfur metabolism node41->Sulfur metabolism Sulfite Sulfite->node37 Sulfite->Sulfur metabolism node42->Pyruvate node42->Sulfite node43->node21 node43->Taurine and hypotaurine metabolism node45 1.4.1.- node43->node45 node46 node43->node46 Sulfur dioxide node44 L-Alanine node45->node42 node46->Sulfur dioxide node46->node44 node47->Propanoate metabolism node48 node48->node47 node48->node53 node48->Homocysteine node49 O-Succinyl -L-homoserine node49->node48 node60 2.5.1.- node49->node60 node50 node50->node49 node51 L-Homoserine node51->node50 node52 node51->node52 node65 O-Acetyl -L-homoserine node52->node65 node53->node30 node54 L-Aspartate node55 node54->node55 node56 L-4 -Aspartyl-phosphate node55->node56 node57 node56->node57 node58 L-Aspartate -4-semialdehyde node57->node58 node59 node59->node51 node59->node58 node60->Homocysteine node61 node61->Homocysteine node62 node64 S-D -Ribosyl-L -homocysteine node62->node64 node105 S-Methyl -5-thio -D-ribose node62->node105 node63 node63->Homocysteine node64->node63 node65->node7 node65->node48 node66 S-Adenosyl -L-homocysteine node66->node61 node66->node62 node67 node67->node66 node68 7 Homocysteine->node68 Homocysteine Homocysteine->node69 node91 Homocysteine->node91 node92 Homocysteine->node92 node93 Homocysteine->node93 node94 Homocysteine->node94 node69->node53 Aspartate metabolism Aspartate metabolism->node54 Homocystine node70 node70->Homocysteine node70->Homocystine node71 L-Methionine S -oxide node73 node71->node73 node74 node71->node74 node72 N-Formyl -L-methionine node76 L-Methionine node73->node76 node74->node76 node75 node75->node72 node75->node76 node77 node76->node77 node78 node76->node78 node83 node76->node83 node84 node76->node84 node79 Aminoacyl -L -methyonine node77->node79 Methanethiol node78->Methanethiol node80 node80->node76 node81 node81->node76 MtnE MtnE->node76 node82 4-Methylthio -2-oxobutanoate node82->node80 node82->node81 node82->MtnE node83->node82 node89 S-Adenosyl -L-methionine node84->node89 node85 3-Methylthio -propionate node86 node86->node85 node87 node87->node82 node88 1,2 -Dihdroxy -3-keto -5-methyl -thiopentene node88->node86 node88->node87 node89->node67 node96 node89->node96 node98 node89->node98 node90 1 node91->node76 node91->node90 node92->node76 node93->node76 node94->node76 node95 1-Aminocyclopropane -1-carboxylate node97 node95->node97 Ethylene node96->node95 node102 S-Methyl -5-thioadenosine node96->node102 node97->Ethylene node99 S-Adenosyl -methioninamine node98->node99 node100 node99->node100 node101 node99->node101 node100->node102 node101->node102 node102->node62 node103 node102->node103 node107 node102->node107 node103->node105 node104 node106 S-Methyl -5-thio -D-ribose 1 -phosphate node104->node106 node105->node104 node107->node106 node108 node109 S-Methyl -5-thio -D-ribulose 1 -phosphate node108->node109 node110 node109->node110 node111 2,3 -Diketo -5-methyl -thiopentyl-1 -phosphate node110->node111 node112 node111->node112 node112->node88 node113 2-Hydroxy -3-keto -5-methylthiopentenyl -1-phosphate node112->node113 node113->node112 Sulfur metabolism->Homocysteine node106->node108 Methionine salvage print "