These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Studies on the nature of transition-metal-ion-mediated binding of triazine dyes to enzymes. The interaction of procion red MX-8B with carboxypeptidase G-2.
    Author: Hughes P, Sherwood RF, Lowe CR.
    Journal: Eur J Biochem; 1984 Oct 01; 144(1):135-42. PubMed ID: 6548187.
    Abstract:
    Several reactive azoic dichlorotriazinyl dyes specifically and irreversibly inactivate the folate-degrading enzyme carboxypeptidase G-2 at a site competitive with the enzyme substrates methotrexate (4-amino-N10-methylfolic acid) and p-aminobenzoyl-L-glutamate. Although the less reactive monochlorotriazinyl dye, Procion red H-8BN, is unable to inactivate the enzyme, it is capable of marked inhibition of inactivation by dichlorotriazinyl dyes in the presence of Zn2+. Zinc ions and, to a lesser extent other first row transition metal ions, significantly enhance the affinity of Procion red H-8BN and its analogues Procion red MX-8B and Procion red MX-2B, for carboxypeptidase G-2. It is proposed that this effect is mediated through the formation of a specific tetracoordinate Zn2+ complex between the azo linkage and adjacent sulphonate and hydroxyl functions of the dye and an appropriate ligand on the protein. Carboxypeptidase G-2 quantitatively inactivated with the dichlorotriazinyl dye, Procion red MX-8B, contains approximately 1 mol dye/mol subunit of Mr 42000. Proteolytic cleavage of the labelled enzyme and resolution of the peptides by reverse-phase high-performance liquid chromatography yields a principal red peptide which on amino acid sequence analysis results in the identification of the dye binding domain. The affinity label, Procion red MX-8B, is believed to be attached to the hydroxylic side chain of Thr-279.
    [Abstract] [Full Text] [Related] [New Search]