A kinetic study of the coupled iron-ceruloplasmin catalyzed oxidation of ascorbate in the presence of albumin

✍ Scribed by Rolf Arthur Løvstad

• Book ID: 104639211
• Publisher: Springer Netherlands
• Year: 1995
• Tongue: English
• Weight: 277 KB
• Volume: 8
• Category: Article
• ISSN: 1572-8773
• DOI: 10.1007/bf00141606

✦ Synopsis

Ascorbate is catalytically oxidized by a coupled iron-ceruioplasmin system, the iron ions functioning as a red/ox cycling intermediate between ceruloplasmin and ascorbate. Serum albumin, an iron binding compound, was found to stimulate the ascorbate oxidation rate. It is proposed that ferrous ions react more rapidly with ceruloplasmin when they are bound to albumin. AKm value of 39/~M was estimated for Fe2+-albumin. Citrate and urate inhibit the iron-ceruloplasmin-dependent ascorbate oxidation by chelating ferric ions. In the presence of albumin only citrate reduced the oxidation rate, the observation suggesting the following order of iron binding ability: citrate > albumin > urate. Physiological aspects of the results have been discussed.