many important biomolecules are derived from amino acids tyrosine serves as a family of neurotransmitters known as catecholamine first tyrosine hydroxylase adds a hydroxyl group to tyrosine converting it to dopa this reaction is coupled to the reduction of oxygen to water and also requires the cofactor tetrahydrobiopterin abbreviated as bh4 which is oxidized to the hydrobiopterin abbreviated as bh2 next aromatic amino acid decarboxylase removes the carboxyl group from dopa producing carbon dioxide and dopamine this reaction requires the cofactor paradoxical phosphate or plp recall that plb plays a huge role in amino acid metabolism mostly in various immunotransferases which i talked about in my previous video on amino acid metabolism dopamine is a neurotransmitter that plays a major role in our brain's reward system as well as motor control the neurological disorder parkinson's disease which affects the motor system is associated with an under production of dopamine and it has traditionally been treated by administering l-dopa dopamine can undergo hydroxylation at the beta carbon by dopamine beta hydroxylase which is coupled to the reduction of oxygen to water and oxidation of scorpio to dehydroascorbate the product norepinephrine also known as noradrenaline can be methylated by phenol ethanolamine and methyltransferase to form epinephrine also known as adrenaline with s adenosine methionine abbreviated as sam as the donor of the methyl group both norepinephrine and epinephrine are hormone secreted by adrenal medulla in response to short-term stress they are part of the sympathetic nervous system that plays a role in fight or flight response by increasing blood flow dilating pupils and other physiological effects norepinephrine also serves as a neurotransmitter that function in alertness arousal and readiness for action dopamine norepinephrine and epinephrine belong to a family of neurotransmitter called catacholamines on the other hand tryptophan can undergo hydroxylation by tryptophan hydroxylase to form 5-hydroxyl tryptophan this reaction is analogous to tyrosine hydroxylase which is coupled to the reduction of oxygen to water and the oxidation of tetrahedral biopthorium to dihydrobiopterin 5-hydroxy cryptofan can then undergo decarboxylation by dependent aromatic amino acid decarboxylase to form serotonin which is a key neurotransmitter that plays a major role in modulating mood serotonin can be further converted to melatonin in two steps first serotonin and acetyl transferase abbreviated as snat transfers acetyl group from acetyl-coa onto the amino group of serotonin producing an acetyl serotonin which is subsequently methylated by methyltransferase to produce melatonin melatonin is a hormone produced by the pineal gland at night to regulate the sleep wake cycle tryptophan also serves as a precursor to the plant hormone indul3 acetate or oxide which promotes plant elongation histidine can be decarboxylated by histamine decarboxylase to form histamine which also requires the cofactor paradoxical phosphate histamine plays an important role in facial dilation during inflammatory reaction as well as serving as neurotransmitter that promotes wastefulness and homeostatic functions glutamate is the major excitatory neurotransmitter in our brain and it can also undergo the carboxylation by plp-dependent glutamate decarboxylase to form gamma-aminobutyrate abbreviated as gaba which is the major inhibitory neurotransmitter in our brain the gaseous chemical signal nitric oxide is derived from arginine catalyzed by nitric oxide synthase which is coupled to the reduction of oxygen to water and oxidation nadph to nadp plus producing nitric oxide and citrulline which is the intermediate of the urea cycle nitric oxide serves as a powerful facial dilator through the soluble guanolyo cyclase which increases the concentration of cyclic gmp lastly acetylcholine is derived from serine first serum decarboxylase converts serine to ethanolamine which is subsequently converted to choline by three repeating steps of methyl transferases with s adenosine methodone as the methyl donor choline acetyl transfer is abbreviated as chat then condenses choline and acetylcholine to form acetylcholine which is a chief neurotransmitter at the neuromuscular junction and the parasympathetic nervous system that promotes rest and digest besides chemical signals some coenzymes are also derived from amino acids tryptophan can give rise to niacin or vitamin b3 which serves as a precursor to the co-emphasized nad and nadp cysteine can give rise to coenzyme a which plays a role in oxidation of fatty acids and pyruvate lastly glutamate can give rise to folate or vitamin b9 which plays a role in many one carbon transfer reactions many membrane lipids are derived from searing serum combines with palmitoulocoate to form sphingolipids such as gangliosides cerebrosides and sprinkle myelin serum combines with ctp diazoglycerol to form phosphatidylserine abbreviated as ps catalyzed by phosphatidylserine synthase abbreviated as pss phosphatidylserine decarboxylase can convert phosphatal serine to phosphotidoethynalamine abbreviated as pe which can be converted to phosphatidylcholine abbreviated as pc by three repeating steps of methyl transferases ethanolamine can also give rise to fossil tidal ethanolamine while choline can also give rise to fossil tidal choline through the kennedy pathway fossil tidal searing fossil tidal ethanolamine and phosphatidylcholine are some of the phospholipids that make up our cell membrane more details about membrane lipid biosynthesis will be covered in a future video polyamines are synthesized from the urea cycle intermediate or methane first the plp-dependent enzyme ornithin decarboxylase converts ornithine to protrusion which combines with decarboxylated acetyl steel methionine to form decarboxylated acetone steal homocysteine as well as permitting catalyzed by purple amino transfer is one abbreviated as pad 1. pat 2 converts spermatine to sperming spermatin and sperming are known as polyamines that play a role in dna packaging trimethylyzing can give rise to currenting in a series of steps carotene is important in transporting fatty acid coat from the cytosol into the mitochondrial matrix for fatty acid oxidation creatine is derived from glycine and arginine first amedenal transfers condenses glycine with arginine to form ornithine and guanadino acetate which is subsequently methylated to form creatine at rest muscle tissues can store excess atp in creatine by converting it to phosphocreatine catalyzed by creatine synthase during bursts of heavy activity the same enzyme regenerates atp from adp by converting phosphocreatine to creatine therefore creatine serves as an atp buffer in muscle tissues glutathione is derived from glutamate cysteine and glycine first gamma gluon ml cysteine synthase condenses glutamate with cysteine to form a dipeptide which condenses with glycine to form reduced glutathione both condensation reactions require the hydrolysis of atp to adp and inorganic phosphate glutathione plays an important role as an antioxidant against the highly reactive hydrogen peroxide which i've covered in my video titled biological oxidation and reduction note that many pathways i've covered so far required the methyl donor as the dioceal methionine which is derived from methionine by methodology adenosine transferase therefore methionine also serves as a precursor to epinephrine melatonin phosphatidylcholine polyamines and creatine heme the coordinated complex that binds oxygen and hemoglobin and myoglobin is derived from glycine first glycine condenses with succinylchoid to form delta aminolevityline which undergoes a series of six reactions to form protoporphyrin the organic component of heme protoporphyrin conjugates with iron cation to form heme by ferrochelatase him is incorporated as hemoglobin in red blood cells and functions in transporting oxygen between lungs and body tissues heme gives the blood its red color dying red blood cells can be degraded to heme heme oxygenase then converts him to biliverdin which releases carbon monoxide and free iron cation next spillovernite reductase reduces spillovered into bilirubin which is coupled to the oxidation of nadph to nadp plus biliverdin and bilirubin are responsible to the change in color of bruises which changes from initial dark purple to the green color of biliverdin and the yellow color of bilirubin bilirubin is largely insoluble and travels in the bloodstream as a complex with serum albumin in the liver bilirubin is transformed into the biopigment bilirubin that glucaronide which is water soluble and combines with bile salts and fats to form bile bio is stored in a gallbladder and it to small intestine to emulsify lipids primary bowel acids are synthesized from cholesterol in the liver in the intestines primary bioacids are conjugated with touring or glycine residues to form secondary bowel acids which are the major bile salts taurine is synthesized from cysteine in a few steps bilirubin is ultimately degraded to the colorless urability by microbial enzymes in the intestine some urobilinogen is reabsorbed into the blood and transported to kidney where it is converted to uralin the compound that gives urine its yellow color microbes in the intestine converts the remaining uropilinogen into circle billing which gives species the red brown color