Tyrosine: Difference between revisions

Revision as of 00:35, 10 February 2025

Tyrosine

Tyrosine is an amino acid that is used in the biosynthesis of proteins. It is a non-essential amino acid with the chemical formula C_H__NO_. Tyrosine is encoded by the genetic code as the codons UAC and UAU.

Structure and Properties

Tyrosine is classified as a polar amino acid due to the presence of a hydroxyl group in its side chain. This hydroxyl group makes tyrosine more hydrophilic than other amino acids such as phenylalanine. The presence of the aromatic ring in its structure also allows tyrosine to participate in pi stacking interactions.

Biosynthesis

In plants and microorganisms, tyrosine is synthesized from prephenate, a product of the shikimate pathway. In animals, tyrosine is derived from phenylalanine through the action of the enzyme phenylalanine hydroxylase. This conversion is crucial for the metabolism of phenylalanine and the production of tyrosine.

Biological Role

Tyrosine is a precursor to several important neurotransmitters and hormones, including dopamine, norepinephrine, and epinephrine. It is also involved in the synthesis of melanin, the pigment responsible for the color of skin and hair.

Metabolism

Tyrosine is metabolized in the liver by the enzyme tyrosine aminotransferase, which converts it into p-hydroxyphenylpyruvate. This compound is further metabolized into homogentisate, which is eventually broken down into fumarate and acetoacetate, intermediates in the citric acid cycle.

Degradation

The degradation of tyrosine involves several steps, ultimately leading to the production of energy and the generation of metabolic intermediates. Disorders in tyrosine metabolism can lead to conditions such as tyrosinemia and alcaptonuria.

Related Pages

References

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-'''Tyrosine''' (symbol '''Tyr''' or '''Y''') is one of the 20 standard [[amino acids]] that are used by cells to synthesize [[proteins]]. It is a non-essential amino acid with a polar side group. Its codons are UAC and UAU. The word "tyrosine" is from the Greek ''tyros'', meaning cheese, as it was first discovered in 1846 by German chemist [[Justus von Liebig]] in the protein casein from cheese.
+== Tyrosine ==
-== Structure ==
+[[File:Tyrosine-spin.gif|thumb|right|3D model of tyrosine]]
-Tyrosine is a white crystalline solid that is soluble in water and alcohol. It is an [[aromatic amino acid]] like [[phenylalanine]] and [[tryptophan]]. It contains a phenol group, making it a polar, aromatic amino acid. It is encoded by the codons UAC and UAU in genetic code.
+[[File:L-Tyrosin_-_L-Tyrosine.svg|thumb|right|Chemical structure of L-Tyrosine]]
-== Function ==
+'''Tyrosine''' is an [[amino acid]] that is used in the biosynthesis of [[proteins]]. It is a non-essential amino acid with the chemical formula C_H__NO_. Tyrosine is encoded by the [[genetic code]] as the codons UAC and UAU.
-Tyrosine is important for the structure of almost all proteins in the body. It is also a precursor to several important substances, including [[dopamine]], [[norepinephrine]], and [[epinephrine]], which are all [[neurotransmitters]] that help nerve cells communicate and influence mood. Tyrosine is also involved in the production of [[melanin]], which is the pigment responsible for hair and skin color.
-== Dietary Sources ==
+== Structure and Properties ==
-Tyrosine is found in many high-protein food products such as chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds.
-== Deficiency and Disease ==
+Tyrosine is classified as a polar amino acid due to the presence of a hydroxyl group in its side chain. This hydroxyl group makes tyrosine more hydrophilic than other amino acids such as [[phenylalanine]]. The presence of the aromatic ring in its structure also allows tyrosine to participate in [[pi stacking]] interactions.
-A deficiency in tyrosine can lead to conditions such as low blood pressure, low body temperature, and an underactive thyroid. In rare cases, a genetic disorder called [[Tyrosinemia]] can occur, which affects the body's ability to break down tyrosine.
-== See Also ==
+== Biosynthesis ==
+[[File:Tyrosine_biosynthesis.svg|thumb|right|Biosynthesis of tyrosine]]
+In [[plants]] and [[microorganisms]], tyrosine is synthesized from [[prephenate]], a product of the [[shikimate pathway]]. In [[animals]], tyrosine is derived from phenylalanine through the action of the enzyme [[phenylalanine hydroxylase]]. This conversion is crucial for the metabolism of phenylalanine and the production of tyrosine.
+== Biological Role ==
+Tyrosine is a precursor to several important [[neurotransmitters]] and [[hormones]], including [[dopamine]], [[norepinephrine]], and [[epinephrine]]. It is also involved in the synthesis of [[melanin]], the pigment responsible for the color of skin and hair.
+== Metabolism ==
+[[File:Conversion_of_phenylalanine_and_tyrosine_to_its_biologically_important_derivatives.png|thumb|right|Conversion of phenylalanine and tyrosine to its biologically important derivatives]]
+Tyrosine is metabolized in the liver by the enzyme [[tyrosine aminotransferase]], which converts it into [[p-hydroxyphenylpyruvate]]. This compound is further metabolized into [[homogentisate]], which is eventually broken down into [[fumarate]] and [[acetoacetate]], intermediates in the [[citric acid cycle]].
+== Degradation ==
+[[File:Tyrosinedegradation2.png|thumb|right|Pathway of tyrosine degradation]]
+The degradation of tyrosine involves several steps, ultimately leading to the production of energy and the generation of metabolic intermediates. Disorders in tyrosine metabolism can lead to conditions such as [[tyrosinemia]] and [[alcaptonuria]].
+== Related Pages ==
+* [[Phenylalanine]]
 * [[Amino acid]]
-* [[Protein]]
+* [[Protein biosynthesis]]
 * [[Neurotransmitter]]
-* [[Tyrosinemia]]
+== References ==
+{{Reflist}}
 [[Category:Amino acids]]
-[[Category:Proteinogenic amino acids]]
+[[Category:Biochemistry]]
-[[Category:Glucogenic amino acids]]
-{{stub}}