A new solid-phase chelator with high affinity and selectivity for calcium: Parvalbumin-polyacrylamide

✍ Scribed by Pavel Lehky; Michelle Comte; Edmond H. Fischer; Eric A. Stein

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 655 KB
• Volume: 82
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(77)90144-0

✦ Synopsis

A solid-phase chelator for calcium was prepared by linking parvalbumin (a muscle calcium-binding protein of remarkable stability) to the polyacrylamide matrix of Bio-Gel P-60. The immobilized parvalbumin can be used repeatedly, and, due to its remarkable affinity for calcium, it is capable of lowering calcium concentration to < lo-r0 M at neutrality. The affinity for calcium remains relatively high even at pHs as low as 4-5, at which complexants such as EDTA, EGTA, or Chelex would be quite inefficient. As immobilized parvalbumin binds Mg2+ with an apparent Kdiss 3.5 orders of magnitude higher than that of Ca2+, it can be used to control calcium concentrations even in the presence of magnesium. The affinity for calcium of any strong complexant can be determined by measuring Ca2+ distribution between this complexant and the solid-phase parvalbumin. Due to its outstanding affinity and selectivity for calcium, immobilized parvalbumin could prove to be a powerful tool in investigating the role of calcium in the regulation of metabolic processes.