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Showing 81 - 90 of 111423 pathways
PathBank ID Pathway Chemical Compounds Proteins

SMP0121063

Pw122332 View Pathway
Metabolite

Juvenile Hormone Synthesis

Drosophila melanogaster
Juvenile hormones in insects are important for their growth before their adulthood, preventing metamorphosis if they undergo one. In Drosophila, only juvenile hormone III has been identified, while others exist in butterflies and moths. Synthesis of various forms of juvenile hormone III (JH III) start with farnesyl diphosphate interacting with an uncharacterized phosphatase protein, forming farnesol. Farnesol then interacts with NADP+ dependent farensol dehydrogenase, which removes a hydrogen ion from the hydroxyl group in order to form farnesal. Farnesal then enters the mitochondria and interacts with another uncharacterized aldehyde dehydrogenase which allows it to form farnesoic acid. Farnesoic acid can then interact with an unknown protein, similar to farnesoate epoxidase in Bombyx mori, in order to form juvenile hormone III acid (JH III acid). JH III acid can then interact with epoxide hydrolase in the membrane of the endoplasmic reticulum, forming the final product of this pathway, juvenile hormone III acid diol (JH III acid diol). It can also interact with juvenile hormone acid O-methyltransferase in order to form JH III, which is used in another set of reactions in this pathway. If farnesoic acid does not interact with the unknown protein, it may interact with juvenile hormone acid O-methyltransferase to form methyl farnesoate. Methyl farnesoate can then interact with a different unknown protein similar, to methyl farnesoate epoxidase in Diploptera punctata, in order to form JH III. In the mitochondria, JH III can interact with carboxylic ester hydrolase in order to form JH III acid, which then can form the final product, or form JH III again. Alternately, JH III can interact with epoxide hydrolase in the membrane of the endoplasmic reticulum, forming juvenile hormone III diol. This product then interacts with carboxylic ester hydrolase in the mitochondria, forming JH III acid diol, again, the end product of this pathway.

Metabolic

SMP0121068

Pw122337 View Pathway
Metabolite

Ether Lipid Metabolism

Drosophila melanogaster
Ether lipids are typically glycerophospholipids where the glycerol backbone has lipids attached by both an ether bond at the sn-1 position and an acyl group at the sn-2 position. This pathway starts with dihydroxyacetone phosphate acyl ester which comes from glycerophospholipid metabolism. In the peroxisome, it reacts with a long chain alcohol, catalyzed by alkyldihydroxyacetonephosphate synthase, and forms an alkyl-glycerone 3-phosphate. Following this, the enzyme acylglycerone-phosphate reductase adds a hydrogen ion to the alkyl-glycerone 3-phosphate, forming a 1-alkyl-sn-glycerol 3-phosphate. Following this, a long-chain fatty acyl group is added, taken from a long-chain fatty acyl-CoA, and catalyzed by an acyltransferase to form a 2-acyl-1-alkyl-sn-glycero-3-phosphate. The phosphate is then removed in a reaction catalyzed by putative phosphatide phosphatase, forming 2-acyl-1-alkyl-sn-glycerol. This can then have a phosphoethanolamine group added by an ethanolaminephosphotransferase in the endoplasmic reticulum membrane, to form 2-acyl-1-alkyl-sn-glycero-3-phosphoethanolamine. This compound then is acted upon by a plasmanylethanolamine desaturase to form O-1-alk-1-enyl-2-acyl-sn-glycero-3-phosphoethanolamine. O-1-alk-1-enyl-2-acyl-sn-glycero-3-phosphoethanolamine can then react via phospholipase A2 to form a 1-alkenylglycerophosphoethanolamine, one of the end products of this pathway, or react via phospholipase D to form a 2-acyl-1-(1-alkenyl)-sn-glycero-3-phosphate, another end product of this pathway. It can also react reversibly using an ethanolaminephosphotransferase in the endoplasmic reticulum membrane to form or be formed from a 1-alkenyl-2-acylglycerol. Alternatively, the 2-acyl-1-alkyl-sn-glycerol can react with CDP-choline, catalyzed by a diacylglycerol cholinephosphotransferase, in order to form a 1-radyl-2-acyl-sn-glycero-3-phosphocholine. This can then react using phospholipase A2 as the enzyme to form a 1-organyl-2-lyso-sn-glycero-3-phosphocholine which can then react using lysophosphatidylcholine acyltransferase in the endoplasmic reticulum membrane to reform 1-radyl-2-acyl-sn-glycero-3-phosphocholine. Alternatively, it can react with the lysophosphatidylcholine acyltransferase to form 2-O-acetyl-1-O-hexadecyl-sn-glycero-3-phosphocholine, also known as platelet-activating factor, the final end product of this pathway. This platelet-activating factor can then interact with platelet-activating factor acetylhydrolase to reform 1-organyl-2-lyso-sn-glycero-3-phosphocholine.

Metabolic

SMP0000015

Pw000004 View Pathway
Metabolite

Glutathione Metabolism

Homo sapiens
Glutathione (GSH) is an low-molecular-weight thiol and antioxidant in various species such as plants, mammals and microbes. Glutathione plays important roles in nutrient metabolism, gene expression, etc. and sufficient protein nutrition is important for maintenance of GSH homeostasis. Glutathione is synthesized from glutamate, cysteine, and glycine sequentially by gamma-glutamylcysteine synthetase and GSH synthetase. L-Glutamic acid and cysteine are synthesized to form gamma-glutamylcysteine by glutamate-cysteine ligase that is powered by ATP. Gamma-glutamylcysteine and glycine can be synthesized to form glutathione by enzyme glutathione synthetase that is powered by ATP, too. Glutathione exists oxidized (GSSG) states and in reduced (GSH) state. Oxidation of glutathione happens due to relatively high concentration of glutathione within cells.

Metabolic

SMP0000058

Pw000150 View Pathway
Metabolite

Starch and Sucrose Metabolism

Homo sapiens
Amylase enzymes secreted in saliva by the parotid gland and in the small intestine play an important role in initiating starch digestion. The products of starch digestion are but not limited to maltotriose, maltose, limit dextrin, and glucose. The action of enterocytes of the small intestine microvilli further break down limit dextrins and disaccharides into monosaccharides: glucose, galactose, and fructose. Once released from starch or once ingested, sucrose can be degraded into beta-D-fructose and alpha-D-glucose via lysosomal alpha-glucosidase or sucrose-isomaltase. Beta-D-fructose can be converted to beta-D-fructose-6-phosphate by glucokinase and then to alpha-D-glucose-6-phosphate by the action of glucose phosphate isomerase. Phosphoglucomutase 1 can then act on alpha-D-glucose-6-phosphate (G6P) to generate alpha-D-glucose-1-phosphate. Alpha-D-glucose-1-phosphate (G6P) has several possible fates. It can enter into gluconeogenesis, glycolysis or the nucleotide sugar metabolism pathway. UDP-glucose pyrophosphorylase 2 can convert alpha-D-glucose-1-phosphate into UDP-glucose, which can then be converted to UDP-xylose or UDP-glucuronate and, eventually to glucuronate. UDP-glucose can also serve as a precursor to the synthesis of glycogen via glycogen synthase. Glycogen is an analogue of amylopectin (“plant starch”) and acts as a secondary short-term energy storage for animal cells. It’s formed primarily in liver and muscle tissues, but is also formed at secondary sites such as the central nervous system and the stomach. In both cases it exists as free granules in the cytosol. Glycogen is a crucial element of the glucose cycle as another enzyme, glycogen phosphorylase, cleaves off glycogen from the nonreducing ends of a chain to producer glucose-1-phosphate monomers. From there, the glucose-1-phosphate monomers have three possible fates: (1) enter the glycolysis pathway as glucose-6—phosphate (G6P) to generate energy, (2) enter the pentose phosphate pathway to produce NADPH and pentose sugar, or (3) enter the gluconeogenesis pathway by being dephosphorylated into glucose in liver or kidney tissues. To initiate the process of glycogen chain-lengthening, glycogenin is required because glycogen synthase can only add to existing chains. This action is subsequently followed by the action of glycogen synthase which catalyzes the formation of polymers of UDP-glucose connected by (α1→4) glycosidic bonds to form a glycogen chain. Importantly, amylo (α1→4) to (α1→6) transglycosylase catalyzes glycogen branch formation via the transfer of 6-7 glucose residues from a nonreducing end with greater than 11 residues to the C-6 OH- group in the interior of a glycogen molecule.

Metabolic

SMP0012052

Pw012914 View Pathway
Metabolite

AMP Degradation (Hypoxanthine Route)

Arabidopsis thaliana
Purine nucleotides are eventually degraded to ammonia and carbon dioxide. This pathway follows the degradation of AMP to a urate intermediate in the cytosol via xanthine conversion from hypoxanthine. First, AMP deaminase catalyzes the conversion of AMP is into IMP. Second, the predicted enzyme 5′-nucleotidase (coloured orange in the image) is theorized to convert IMP into inosine. Third, ribonucleoside hydrolase converts inosine into hypoxanthine. Fourth, xanthine dehydrogenase is an enzyme that requires [2Fe-2S] cluster, FAD, and Moco as cofactors for catalyzing two subsequent reaction in the AMP degradation pathway: the conversion of hypoxanthine into xanthine and the conversion of xanthine into urate.

Metabolic

SMP0000007

Pw000011 View Pathway
Metabolite

beta-Alanine Metabolism

Homo sapiens
Beta-alanine, 3-aminopropanoic acid, is a non-essential amino acid. Beta-Alanine is formed by the proteolytic degradation of beta-alanine containing dipeptides: carnosine, anserine, balenine, and pantothenic acid (vitamin B5). These dipeptides are consumed from protein-rich foods such as chicken, beef, pork, and fish. Beta-Alanine can also be formed in the liver from the breakdown of pyrimidine nucleotides into uracil and dihydrouracil and then metabolized into beta-alanine and beta-aminoisobutyrate. Beta-Alanine can also be formed via the action of aldehyde dehydrogenase on beta-aminoproionaldehyde which is generated from various aliphatic polyamines. Under normal conditions, beta-alanine is metabolized to aspartic acid through the action of glutamate decarboxylase. It addition, it can be converted to malonate semialdehyde and thereby participate in propanoate metabolism. Beta-Alanine is not a proteogenic amino acid. This amino acid is a common athletic supplementation due to its belief to improve performance by increased muscle carnosine levels.

Metabolic

SMP0000008

Pw000042 View Pathway
Metabolite

Phenylalanine and Tyrosine Metabolism

Homo sapiens
In man, phenylalanine is an essential amino acid which must be supplied in the dietary proteins. Once in the body, phenylalanine may follow any of three paths. It may be (1) incorporated into cellular proteins, (2) converted to phenylpyruvic acid, or (3) converted to tyrosine. Tyrosine is found in many high protein food products such as soy products, chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds. Tyrosine can be converted into L-DOPA, which is further converted into dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Depicted in this pathway is the conversion of phenylalanine to phenylpyruvate (via amino acid oxidase or tyrosine amino transferase acting on phenylalanine), the incorporation of phenylalanine and/or tyrosine into polypeptides (via tyrosyl tRNA synthetase and phenylalyl tRNA synthetase) and the conversion of phenylalanine to tyrosine via phenylalanine hydroxylase. This reaction functions both as the first step in tyrosine/phenylalanine catabolism by which the body disposes of excess phenylalanine, and as a source of the amino acid tyrosine. The decomposition of L-tyrosine begins with an α-ketoglutarate dependent transamination through the tyrosine transaminase to para-hydroxyphenylpyruvate. The next oxidation step catalyzed by p-hydroxylphenylpyruvate-dioxygenase creates homogentisate. In order to split the aromatic ring of homogentisate, a further dioxygenase, homogentistate-oxygenase, is required to create maleylacetoacetate. Fumarylacetate is created by the action maleylacetoacetate-cis-trans-isomerase through rotation of the carboxyl group created from the hydroxyl group via oxidation. This cis-trans-isomerase contains glutathione as a coenzyme. Fumarylacetoacetate is finally split via fumarylacetoacetate-hydrolase into fumarate (also a metabolite of the citric acid cycle) and acetoacetate (3-ketobutyroate).

Metabolic

SMP0121128

Pw122406 View Pathway
Metabolite

Pancreas Function - Delta Cell

Homo sapiens
Pancreatic delta cells produce somatostatin which functions to inhibit glucagon, insulin, and itself. Somatostatin is stored in granules in the delta cell and is released in response to an increase in blood sugar, calcium, and blood amino acids during absorption of a meal. In the process of somatostatin secretion, glucose must first undergo glycolysis in the mitochondrion to increase ATP in the cell. The inside of the alpha cell then becomes electrically positive due to the closure of potassium channels that were inhibited by ATP. From this closure, the potassium is no longer being shuttled out of the cell, thus depolarizing the cell due to the extra intracellular potassium. The resulting action potential from the increased membrane potential causes the voltage gate calcium channels to open, creating an influx of calcium into the cell. This triggers the exocytosis of somatostatin granules from the delta cell.

Physiological

SMP0002094

Pw002082 View Pathway
Metabolite

Thioredoxin Pathway

Escherichia coli
Thioredoxins are a class of proteins that are used in redox reactions, and are found in all living organisms. In humans, they respond to reactive oxygen species, while in plants they are important for growth, photosynthesis, flowering and seed formation. In E. coli, thioredoxins catalyze a number of redox reactions, and are important in stress response, as well as other functions. In this pathway, oxidized thioredoxin is reduced by thioredoxin reductase, in order to form reduced thioredoxin. This reaction also uses NADPH as a cofactor. Reduced thioredoxin then, as part of a redox reaction, acts as the oxidizing agent and converts an oxidized electron acceptor into a reduced electron acceptor. This then produces oxidized thioredoxin, which can be further reduced and reused in other redox reactions.

Metabolic

SMP0000059

Pw000162 View Pathway
Metabolite

Urea Cycle

Homo sapiens
Urea, also known as carbamide, is a waste product made by a large variety of living organisms and is the main component of urine. Urea is created in the liver, through a string of reactions that are called the Urea Cycle. This cycle is also called the Ornithine Cycle, as well as the Krebs-Henseleit Cycle. There are some essential compounds required for the completion of this cycle, such as arginine, citrulline and ornithine. Arginine cleaves and creates urea and ornithine, and the reactions that follow see urea residue build up on ornithine, which recreates arginine and keeps the cycle going. Ornithine is transported to the mitochondrial matrix, and once there, ornithine carbamoyltransferase uses carbamoyl phosphate to create citrulline. After this, citrulline is transported to the cytosol. Once here, citrulline and aspartate team up to create argininosuccinic acid. After this, argininosuccinate lyase creates l-arginine. L-arginine finally uses arginase-1 to create ornithine again, which will be transported to the mitochondrial matrix and restart the urea cycle once more.

Metabolic
Showing 81 - 90 of 111423 pathways