Properties of a novel ATPase enzyme in chromaffin granules

Shulamit Cidon*, Nathan Nelson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Membranes were isolated from mitochondria and chromaffin granules of bovine adrenal medullae. The cross-contamination between the two membranes was examined by comparing the radioactive bands on autoradiograms of gels after phosphorylation of the membranes with [γ-32P]-ATP and decoration with [125I]concanavalin A and [125I]protein A with antibody that was raised against chromaffin-granule membranes. It was found that the membranes cross-contaminated each other by less than 10%. The technique of immunodecoration with antibodies against β subunits of proton-ATPases from yeast mitochondria, spinach chloroplasts, and E. coli membranes was used for quantitative estimation of proton-ATPase complexes in chromaffin granules and mitochondrial membranes. It was found that chromaffin-granule membranes contain less than 10% of the amount of proton-ATPase complex in mitochondrial membranes. The specific ATPase activity of chromaffin-granule membranes was on the order of 30 to 50% of the mitochondrial membranes. The ATPase activity of the chromaffin-granule membranes was more sensitive to 4-acetamido-4′-isothiocyano-2,2′-disulfonic acid stilbene and 4-chloro-7-nitrobenzofurazan. It was much less sensitive than the mitochondrial membranes to antibody against β subunit of proton-ATPase from E. coli membranes. After solubilization of chromaffin-granule membranes by octyglucoside and cholate and subsequent centrifugation on sucrose gradient, two different ATPase enzymes were separated. The heavier enzyme was identical to the mitochondrial-ATPase complex, while the lighter enzyme was identified as a novel ATPase, which might be responsible for the special properties of the ATPase activity of chromaffin-granule membranes.

Original languageEnglish
Pages (from-to)499-512
Number of pages14
JournalJournal of Bioenergetics and Biomembranes
Issue number5-6
StatePublished - Dec 1982
Externally publishedYes


  • ATPase
  • chromaffin granules
  • immunodecoration
  • membranes
  • polypeptides


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