Search results
Results from the WOW.Com Content Network
Hydroxyproline is a major component of the protein collagen, [3] comprising roughly 13.5% of mammalian collagen. Hydroxyproline and proline play key roles for collagen stability. [4] They permit the sharp twisting of the collagen helix. [5]
Pros of free feeding cats Convenience: Owners don’t have to worry about maintaining a feeding schedule. Self-regulation: Some cats are natural grazers and can regulate their food intake.
proline. Secondary amino acids, amino acids containing a secondary amine group are sometimes named imino acids, [2] [3] though this usage is obsolescent. [1] The only proteinogenic amino acid of this type is proline, although the related non-proteinogenic amino acids hydroxyproline [4] [5] [6] and pipecolic acid [7] have often been included in studies of this class of compounds.
Furthermore, proline is rarely found in α and β structures as it would reduce the stability of such structures, because its side chain α-nitrogen can only form one nitrogen bond. Additionally, proline is the only amino acid that does not form a red-purple colour when developed by spraying with ninhydrin for uses in chromatography. Proline ...
In protein, hydroxyproline is incorporated into protein by hydroxylation of proline. Pipecolic acid, a heavier analog of proline, is found in efrapeptin. Sarcosine is a N-methylized glycine so its methyl group is used in many biochemical reactions. Azetidine-2-carboxylic acid, which is a smaller homolog of proline in plants.
Hence, this enzyme has one substrate, trans-4-hydroxy-L-proline, and one product, cis-4-hydroxy-D-proline. This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on amino acids and derivatives. The systematic name of this enzyme class is 4-hydroxyproline 2-epimerase.
Hydroxylation occurs at the γ-C atom, forming hydroxyproline (Hyp), which stabilizes the secondary structure of collagen due to the strong electronegative effects of oxygen. [7] Proline hydroxylation is also a vital component of hypoxia response via hypoxia inducible factors. In some cases, proline may be hydroxylated instead on its β-C atom.
Polypeptides targeted for secretion are subsequently hydroxylated by direct addition of molecular oxygen to proline at C-4. [4] Extensin hydroxyproline is uniquely glycosylated with short chains of L-arabinose [8] that further rigidify [9] and increase hydrophilicity. Generally the serine has a single galactose attached. [10]