The effect of ethylenedinitrilotetraacetic acid (EDTA) on the reaction between the guinea-pig C5 convertase and guinea-pig C5

Guinea-pig C5 was reacted with EAC1423 in the washed-cell intermediate assay in the presence of glucose gelatin veronal buffer (GGVB), Zn2+-GGVB (0.025 mM), GGVB2+ containing Ca2+ and/or Mg2+ or EDTA (0.013 M)-GGVB. The EDTA inhibited the formation of competent SAC14235, while Ca2+ and/or Mg2+ had a...

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Bibliographic Details
Published inMolecular immunology Vol. 21; no. 5; p. 383
Main Authors Evans, B D, Amiraian, K
Format Journal Article
LanguageEnglish
Published England 01.05.1984
Subjects
Animals
Cations, Divalent - pharmacology
Complement Activating Enzymes - antagonists & inhibitors
Complement C3-C5 Convertases
Complement C5 - metabolism
Complement C6 - metabolism
Edetic Acid - pharmacology
Guinea Pigs
Humans
Kinetics
Zinc - pharmacology
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Summary:Guinea-pig C5 was reacted with EAC1423 in the washed-cell intermediate assay in the presence of glucose gelatin veronal buffer (GGVB), Zn2+-GGVB (0.025 mM), GGVB2+ containing Ca2+ and/or Mg2+ or EDTA (0.013 M)-GGVB. The EDTA inhibited the formation of competent SAC14235, while Ca2+ and/or Mg2+ had a slight enhancing effect compared to GGVB alone and Zn2+ gave a four-fold increase. Similar results were obtained by using human C5 with guinea-pig C5 convertase and functionally pure guinea-pig C6, C7, C8 and C9. When guinea-pig C6 was incorporated into these various reaction mixtures with guinea-pig C5, its addition markedly reduced the inhibition by EDTA, while Zn2+ still showed an enhancing effect. These results demonstrate that EDTA inhibited formation of competent SAC14235 by preventing activation of C5. The association of C6 with C5 can partially overcome the inhibition of C5 conversion by EDTA and may account for C5 activity in reaction mixtures containing C-EDTA.
ISSN:0161-5890
DOI:10.1016/0161-5890(84)90035-X