二辛可宁酸（4,4'-二羧基-2,2'-联喹啉）蛋白质测定中的pH值与缓冲作用

pH and buffering in the bicinchoninic acid (4,4'-dicarboxy-2,2'-biquinoline) protein assay.

作者信息

Zhang J X, Halling P J

机构信息

Department of Bioscience & Biotechnology, University of Strathclyde, Glasgow, United Kingdom.

出版信息

Anal Biochem. 1990 Jul;188(1):9-10. doi: 10.1016/0003-2697(90)90520-j.

DOI:10.1016/0003-2697(90)90520-j

PMID:2221373

Abstract

The HCO3/CO3(2-) buffer used in the bicinchoninic acid (BCA) protein assay has only weak buffering capacity at the recommended pH (11.25). Consequently the assay is rather sensitive to interference from effectively acid or alkaline samples, particularly in the micro method. Adjustment of pH in these alkaline solutions of high [Na+] is complicated by Na+ errors on the pH electrode. Hence it is recommended to prepare the buffers from known amounts of NaHCO3 and Na2CO3, and to reduce the pH to around 10.7; this offers much better buffering capacity with only a limited reduction in color development.

摘要

用于二辛可宁酸（BCA）蛋白质测定的HCO3/CO3(2-)缓冲液在推荐的pH值（11.25）下缓冲能力较弱。因此，该测定对有效酸性或碱性样品的干扰相当敏感，尤其是在微量法中。在这些高[Na+]的碱性溶液中，pH电极上的Na+误差会使pH调节变得复杂。因此，建议用已知量的NaHCO3和Na2CO3制备缓冲液，并将pH降低至约10.7；这样可以提供更好的缓冲能力，同时显色的降低有限。