Kinetic and equilibrium studies of the interactions of silver ions with poly(A)

✍ Scribed by Yoshikuni Yakabe; Takayuki Sano; Naohisa Kure; Kiyofumi Murakami; Tatsuya Yasunaga

• Publisher: Wiley (John Wiley & Sons)
• Year: 1982
• Tongue: English
• Weight: 434 KB
• Volume: 21
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360210903

✦ Synopsis

Abstract

The interaction of silver ions with poly(A) was studied by potentiometric titration, uv spectrophotometry, and stopped‐flow spectroscopy. For 0 < r~b~ < 0.5, where r~b~ is moles of silver ion bound per mole of nucleotide base, there exists only one type of binding for poly(A). Using McGhee's theory, the binding parameters, such as intrinsic binding constant, number of sites per nucleotide, and cooperativity, were determined from the potentiometric titration data. Using the stopped‐flow method, one relaxation time was observed in 0 < r~0~ < 0.5, where r~0~ is the moles of silver ions added per mole of nucleotide base. The concentration dependences of the relaxation time suggest that the binding of silver ions to poly(A) proceeds through the following mechanism:

equation image

where M is free silver ions, P the free binding sites on poly(A), and C and C′ are two forms of the complex. The nature of the binding of silver ions to poly(A) is also discussed.