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Information about Hydroxylation

Hydroxylation is any chemical process that introduces one or more hydroxyl groups (-OH) into a compound (or radical) thereby oxidizing it. In biochemistry, hydroxylation reactions are often facilitated by enzymes called hydroxylases.

Hydroxylation in proteins

The principal residue to be hydroxylated in proteins is Proline. The hydroxilation occurs at the atom, forming hydroxyproline (Hyp), an essential element of collagen, in turn a necessary element of connective tissue. Proline hydroxylation is also a vital component of hypoxia response via hypoxia inducible factors. In some cases, proline may be hydroxylated instead on its atom. Lysine may also be hydroxylated on its atom, forming hydroxylysine (Hyl).

These three reactions are catalyzed by very large, multi-subunit enzymes prolyl 4-hydroxylase, prolyl 3-hydroxylase and lysyl 5-hydroxylase, respectively. These reactions require iron (as well as molecular oxygen and α-ketoglutarate) to carry out the oxidation, and use ascorbic acid (vitamin C) to return the iron to its reduced state. Deprivation of ascorbate leads to deficiencies in proline hydroxylation, which leads to less stable collagen, which can manifest itself as the disease scurvy. Since vitamin C is rich in citrus fruits, British sailors were given limes to combat scurvy on long ocean voyages; hence, they were called "lymies".

See also

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Protein primary structure and posttranslational modifications
GeneralProtein biosynthesis
N-terminusAcetylation
C-terminusAmidation
LysineMethylation
CysteineDisulfide bond
Serine/ThreoninePhosphorylation
TyrosinePhosphorylation
AsparagineDeamidation
AspartateSuccinimide formation
GlutamineTransglutamination
GlutamateCarboxylation
ArginineCitrullination
ProlineHydroxylation
Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed.

This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide, or the
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Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions.[1] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products.
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Proline (abbreviated as Pro or P) is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that humans can synthesize it.
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4-Hydroxyproline, or hydroxyproline (C5H9O3N), is an uncommon amino acid, abbreviated as HYP, e.g., in Protein Data Bank.

Structure


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Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, [1] making up about 25% of the total protein content.

Uses


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Hypoxia literally means "deficient in oxygen." It can refer to:
  • Hypoxia (medical), a shortage of oxygen in the body. Hypoxaemia is the reduction of oxygen specifically in the blood; anoxia is when there is no oxygen available at all.

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Identifiers
Symbol HIF3A

Entrez 64344
HUGO 15825
OMIM 609976

RefSeq NM_152794
UniProt Q9Y2N7
Other data

Locus Chr. 19 q13 Hypoxia inducible factors (HIFs)
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Hydroxylysine is an amino acid, C6H14N2O3. It is most widely known as a component of collagen. A standard amino acid with the R' group consisting of an amino terminated butyl hydrocarbon chain, with a hydroxyl group on the carbon atom
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Prolyl hydroxylase (or procollagen-proline dioxygenase) is an enzyme involved in the production of collagen, acting to hydroxylate proline to hydroxyproline.

It requires vitamin C as a cofactor.
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Prolyl hydroxylase (or procollagen-proline dioxygenase) is an enzyme involved in the production of collagen, acting to hydroxylate proline to hydroxyproline.

It requires vitamin C as a cofactor.
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Identifiers
Symbol PLOD2

Entrez 5352
HUGO 9082
OMIM 601865

RefSeq NM_000935
UniProt O00469
Other data

Locus Chr. 3 q24 Lysyl hydroxylase (or procollagen-lysine 5-dioxygenase
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Ascorbic acid is an organic acid with antioxidant properties. Its appearance is white to light yellow crystals or powder. It is water soluble. The L-enantiomer of ascorbic acid is commonly known as vitamin C.
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Scurvy
Classification & external resources

Scorbutic gums, a symptom of scurvy
ICD-10 E 54.
ICD-9 267

OMIM 240400
DiseasesDB 13930
MedlinePlus 000355
eMedicine med/2086   derm/521 ped/2073 radio/628
MeSH D012614 Scurvy
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sailor or mariner is a person who navigates water-born vessels or assists in their operation, maintenance, or service. The term can apply to professional mariners, military personnel, and recreational sailors as well as a plethora of other uses.
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Lime may refer to:
  • Lime (fruit), various green to yellow citrus fruits
  • Lime (color), various colors of green
  • Lime (mineral), a group of calcium compounds and minerals in which they predominate

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Phenylalanine hydroxylase (EC 1.14.16.1 ) is an enzyme which catalyses 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:


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Tyrosine hydroxylase or tyrosine 3-monooxygenase is the enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to dihydroxyphenylalanine (DOPA).
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primary structure of a biological molecule is the exact specification of its atomic composition and the chemical bonds connecting those atoms (including stereochemistry). For a typical unbranched, un-crosslinked biopolymer (such as a molecule of DNA, RNA or typical intracellular
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Post-translational modification (PTM) is the chemical modification of a protein after its translation. It is one of the later steps in protein biosynthesis for many proteins. A protein (also called a polypeptide) is a chain of amino acids.
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Protein biosynthesis (synthesis) is the process in which cells build proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription which are then used for translation.
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The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) refers to the end of a protein or polypeptide terminated by an amino acid with a free amine group (-NH2).
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Acetylation (or in IUPAC nomenclature ethanoylation) describes a reaction that introduces an acetyl functional group into an organic compound. Deacetylation is the removal of the acetyl group.
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The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal end, or COOH-terminus) of a protein or polypeptide is the end of the amino acid chain terminated by a free carboxyl group (-COOH).
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amide is one of two kinds of compounds:
  • the organic functional group characterized by a carbonyl group (C=O) linked to a nitrogen atom (N), or a compound that contains this functional group (pictured to the right); or
  • a particular kind of nitrogen anion.

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Lysine (abbreviated as Lys or K)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)(CH2)4NH2.
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Methylation is a term used in the chemical sciences to denote the attachment or substitution of a methyl group on various substrates. This term is commonly used in chemistry, biochemistry, and the biological sciences.
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Cysteine (abbreviated as Cys or C)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)CH2SH. It is not an essential amino acid, which means that humans can synthesize it. Its codons are UGU and UGC.
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In chemistry, a disulfide bond is a single covalent bond derived from the coupling of thiol groups. The linkage is also called an SS-bond or disulfide bridge. The overall connectivity is therefore C-S-S-C.
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Serine (abbreviated as Ser or S)[1] is an organic compound with the formula HO2CCH(NH2)CH2OH. It is one of the 20 naturally occurring proteinogenic amino acids. Its codons are UCU, UCC, UCA, UCG, AGU and AGC.
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Threonine (abbreviated as Thr or T)[1] is an α-amino acid with the chemical formula HO2CCH(NH2)CH(OH)CH3. Its codons are ACU and ACA. This essential amino acid is classified as polar.
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