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  2. Histidine - Wikipedia

    en.wikipedia.org/wiki/Histidine

    Histidine ball and stick model spinning. Histidine (symbol His or H) [2] is an essential amino acid that is used in the biosynthesis of proteins.It contains an α-amino group (which is in the protonated –NH 3 + form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO − form under biological conditions), and an imidazole side chain (which is partially ...

  3. Histidine (data page) - Wikipedia

    en.wikipedia.org/wiki/Histidine_(data_page)

    Hydrogen bond: donor - 3; ... (L-histidine) This page was last edited on 12 April 2023, at 11:40 (UTC). Text is available under the Creative Commons ...

  4. Chemical polarity - Wikipedia

    en.wikipedia.org/wiki/Chemical_polarity

    A completely polar bond is more correctly called an ionic bond, and occurs when the difference between electronegativities is large enough that one atom actually takes an electron from the other. The terms "polar" and "nonpolar" are usually applied to covalent bonds, that is, bonds where the polarity is not complete. To determine the polarity ...

  5. Catalytic triad - Wikipedia

    en.wikipedia.org/wiki/Catalytic_triad

    The range of amino acid residues found at the active sites of hydrolytic enzymes. On the left are the nucleophile, base and acid triad members. On the right are substrates with the cleavable bond indicated by a pair of scissors. Two bonds in beta-lactams can be cleaved (1 by penicillin acylase and 2 by beta-lactamase).

  6. Salt bridge (protein and supramolecular) - Wikipedia

    en.wikipedia.org/wiki/Salt_bridge_(protein_and...

    In chemistry, a salt bridge is a combination of two non-covalent interactions: hydrogen bonding and ionic bonding (Figure 1). Ion pairing is one of the most important noncovalent forces in chemistry, in biological systems, in different materials and in many applications such as ion pair chromatography .

  7. Covalent bond - Wikipedia

    en.wikipedia.org/wiki/Covalent_bond

    Covalent bonds are also affected by the electronegativity of the connected atoms which determines the chemical polarity of the bond. Two atoms with equal electronegativity will make nonpolar covalent bonds such as H–H. An unequal relationship creates a polar covalent bond such as with H−Cl.

  8. Chemical bond - Wikipedia

    en.wikipedia.org/wiki/Chemical_bond

    Molecules that are formed primarily from non-polar covalent bonds are often immiscible in water or other polar solvents, but much more soluble in non-polar solvents such as hexane. A polar covalent bond is a covalent bond with a significant ionic character. This means that the two shared electrons are closer to one of the atoms than the other ...

  9. Peptide bond - Wikipedia

    en.wikipedia.org/wiki/Peptide_bond

    Peptide bond formation via dehydration reaction. When two amino acids form a dipeptide through a peptide bond, [1] it is a type of condensation reaction. [2] In this kind of condensation, two amino acids approach each other, with the non-side chain (C1) carboxylic acid moiety of one coming near the non-side chain (N2) amino moiety of the other.