Inosylyl(3′→5′)inosine (IpI–). Acid–Base and Metal Ion-Binding Properties of a Dinucleoside Monophosphate in Aqueous Solution

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• 作者：Bernd Knobloch ; Andrzej Okruszek ; Helmut Sigel
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：April 7, 2008
• 年：2008
• 卷：47
• 期：7
• 页码：2641 - 2648
• 全文大小：157K
• 年卷期：v.47,no.7(April 7, 2008)
• ISSN：1520-510X

文摘

The acidity constants of the (N7)H⁺ sites of inosylyl(3′→5′)inosine (IpI⁻) were estimated and those of its (N1)H sites were measured by potentiometric pH titrations in aqueous solution (25 °C; I = 0.1 M, NaNO₃). The same method was used for the determination of the stability constants of the 1:1 complexes formed between Mg²⁺, Co²⁺, Ni²⁺, Zn²⁺, or Cd²⁺ (= M²⁺) and (IpI − H)²⁻ and, in the case of Mg²⁺, also of (IpI − 2H)³⁻. The stability constants of the M(IpI)⁺ complexes were estimated. The acidity constants of H(inosine)⁺ and the stability constants of the M(Ino)²⁺ and M(Ino − H)⁺ complexes were taken from the literature. The comparison of these and related data allows the conclusion that, in the M(IpI − H) species, chelates are formed; most likely they are preferably of an N7/N7 type. For the metal ions Co²⁺, Ni²⁺, Zn²⁺, or Cd²⁺, the formation degrees of the chelates are on the order of 60−80%; no chelates could be detected for the Mg(IpI − H) complexes. It is noteworthy that the (N1)H deprotonation, which leads to the M(IpI − H) species, occurs in all M(IpI)⁺ complexes in the physiological pH range of about 7.5 or even below.