Where is tyrosine produced

In plants and most microorganisms, tyr is produced via prephenate , an intermediate on the shikimate pathway. Mammals synthesize tyrosine from the essential amino acid phenylalanine phe , which is derived from food.

The conversion of phe to tyr is catalyzed by the enzyme phenylalanine hydroxylase , a monooxygenase. This enzyme catalyzes the reaction causing the addition of an hydroxyl group to the end of the 6-carbon aromatic ring of phenylalanine, such that it becomes tyrosine.

Some of the tyrosine residues can be tagged with a phosphate group phosphorylated by protein kinases. In its phosphorylated state, it is referred to as phosphotyrosine. Tyrosine phosphorylation is considered to be one of the key steps in signal transduction and regulation of enzymatic activity.

Phosphotyrosine can be detected through specific antibodies. Tyrosine residues may also be modified by the addition of a sulfate group, a process known as tyrosine sulfation. Like the phosphotyrosine antibodies mentioned above, antibodies have recently been described that specifically detect sulfotyrosine.

In the adrenal gland , tyrosine is converted to levodopa by the enzyme tyrosine hydroxylase TH. TH is also the rate-limiting enzyme involved in the synthesis of the catecholamine hormones dopamine , norepinephrine noradrenaline , and epinephrine. The thyroid hormones triiodothyronine T 3 and thyroxine T 4 in the colloid of the thyroid also are derived from tyrosine.

In Papaver somniferum , the opium poppy, tyrosine is used to produce the alkaloid morphine. Tyrosine is also the precursor to the pigment melanin. The decomposition of L-tyrosine syn. The positional description para , abbreviated p , mean that the hydroxyl group and side chain on the phenyl ring are across from each other see the illustration below. The next oxidation step catalyzes by p -hydroxylphenylpyruvate-dioxygenase and splitting off CO 2 homogentisate 2,5-dihydroxyphenylacetate.

In order to split the aromatic ring of homogentisate, a further dioxygenase, homogentistate-oxygenase is required. Thereby, through the incorporation of a further O 2 molecule, maleylacetoacetate is created. Fumarylacetate is created maleylacetoacetate- cis - trans -isomerase through rotation of the carboxyl group created from the hydroxyl group via oxidation.

People with PKU must avoid any phenylalanine in their diets. Because tyrosine is made from phenylalanine, people with PKU can be deficient in tyrosine. Tyrosine is used in protein supplements for people with PKU, but most doctors don't recommend more tyrosine supplements. If you have PKU, your doctor will determine if you need more tyrosine and how much.

Tyrosine is involved in the production of the stress neurotransmitters epinephrine and norepinephrine. Some researchers believe that, under stress, the body isn't able to make enough tyrosine from phenylalanine.

Some animal and human studies suggest that tyrosine supplements may help improve memory and performance under psychological stress. More research is needed. One study suggests that taking tyrosine may help you be more alert after sleep deprivation. Some athletes claim that tyrosine helps their performance. However, there is no proof that this claim is true or safe. Because tyrosine helps the body produce the mood-influencing chemical dopamine, and because people who are depressed often have low levels of tyrosine, researchers thought that tyrosine might help treat depression.

However, studies have found that it has no effect. Preliminary research suggests that tyrosine kinase inhibitors may play a role in the treatment of thyroid cancer. Other studies suggest tyrosine kinase inhibitors may help improve lung function among people who have lung cancer or pulminary fibrosis.

Tyrosine is found in soy products, chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds. Take tyrosine supplements at least 30 minutes before meals, divided into 3 daily doses. Taking vitamins B6, B9 folate , and copper along with tyrosine helps the body convert tyrosine into important brain chemicals.

Doses vary. Talk to your nutritionist or doctor about what dose is right for you. To treat symptoms of sleep deprivation, one study used mg per kilogram of body weight per day.

Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider. People who have migraine headaches should avoid tyrosine, as it can trigger migraine headaches and stomach upset. People with hyperthyroidism or Graves disease should avoid tyrosine supplements because tyrosine may increase levels of thyroid hormone. If you are being treated with any of the following medications, you should not use tyrosine supplements without first talking to your health care provider.

People taking MAOIs should avoid foods and supplements containing tyrosine. MAOIs include:. Thyroid hormone -- Tyrosine is a precursor to thyroid hormone, so it might raise levels too high when taken with synthetic thyroid hormones.

Levodopa L-dopa -- Tyrosine should not be taken at the same time as levodopa, a medication used to treat Parkinson's disease. The quicker a person can switch tasks, the greater their cognitive flexibility. Additionally, supplementing with tyrosine has been shown to benefit those who are sleep deprived.

And while tyrosine may provide cognitive benefits, no evidence has suggested that it enhances physical performance in humans 16 , 17 , Lastly, no research suggests that supplementing with tyrosine in the absence of a stressor can improve mental performance.

Phenylketonuria PKU is a rare genetic condition caused by a defect in the gene that helps create the enzyme phenylalanine hydroxylase Your body uses this enzyme to convert phenylalanine into tyrosine, which is used to create neurotransmitters 4.

However, without this enzyme, your body cannot break down phenylalanine, causing it to build up in the body. The primary way to treat PKU is to follow a special diet that limits foods containing phenylalanine However, because tyrosine is made from phenylalanine, people with PKU can become deficient in tyrosine, which can contribute to behavioral problems Supplementing with tyrosine may be a viable option for alleviating these symptoms, but the evidence is mixed.

In one review, researchers investigated the effects of tyrosine supplementation alongside or in place of a phenylalanine-restricted diet on intelligence, growth, nutritional status, mortality rates and quality of life The researchers analyzed two studies including 47 people but found no difference between supplementing with tyrosine and a placebo.

A review of three studies including 56 people also found no significant differences between supplementing with tyrosine and a placebo on the outcomes measured The researchers concluded that no recommendations could be made about whether tyrosine supplements are effective for the treatment of PKU.

Depression is thought to occur when the neurotransmitters in your brain become unbalanced. Antidepressants are commonly prescribed to help realign and balance them Tyrosine was found to have no antidepressant effects Depression is a complex and varied disorder. This is likely why a food supplement like tyrosine is ineffective at combating its symptoms. Nevertheless, depressed individuals with low levels of dopamine, adrenaline or noradrenaline may benefit from supplementing with tyrosine.

In fact, one study among individuals with dopamine-deficient depression noted that tyrosine provided clinically significant benefits Dopamine-dependent depression is characterized by low energy and a lack of motivation Until more research is available, the current evidence does not support supplementing with tyrosine to treat symptoms of depression It has been supplemented safely at a dose of 68 mg per pound mg per kg of body weight per day for up to three months 15 , 29 , Tyramine is an amino acid that helps regulate blood pressure and is produced by the breakdown of tyrosine.

Tyramine accumulates in foods when tyrosine and phenylalanine are converted to tyramine by an enzyme in microorganisms Cheeses like cheddar and blue cheese, cured or smoked meats, soy products and beer contain high levels of tyramine Antidepressant medications known as monoamine oxidase inhibitors MAOIs block the enzyme monoamine oxidase, which breaks down excess tyramine in the body 2 , 32 , However, it is unknown if supplementing with tyrosine may lead to a buildup of tyramine in the body, so caution is necessary for those taking MAOIs 34 , The thyroid hormones triiodothyronine T3 and thyroxine T4 help regulate growth and metabolism in the body.

Supplementing with tyrosine may influence these hormones This is because tyrosine is a building block for the thyroid hormones, so supplementing with it might raise their levels too high.

Therefore, people who are taking thyroid medications or have an overactive thyroid should be cautious when supplementing with tyrosine. Interestingly, tyrosine is being investigated for alleviating some of the symptoms associated with cognitive decline in older adults 38 , NALT is more water-soluble than its free-form counterpart, but it has a low conversion rate to tyrosine in the body 40 , This means that you would need a larger dose of NALT than tyrosine to get the same effect, making the free-form the preferred choice.