New zwitterionic butanesulfonic acids that extend the alkaline range of four families of Good buffers: evaluation for use in biological systems

Abstract

Four new zwitterionic butanesulfonic acid buffers that are structurally related to four families of Good buffers were evaluated for use in biological systems. These buffers, with pKa values from 7.6 to 10.7, were compared with a variety of other buffers from the same family and with unrelated buffers to determine their effect on enzyme activity and on microbial growth. The activity of four enzymes with optimum pH values in the alkaline range were tested: beta-galactosidase, esterase, phosphodiesterase and alkaline phosphatase. In general, all the Good buffers, including the new butanesulfonic acid buffers, gave good activity; however, there was variation in activity of certain enzymes with certain buffers. Tris, glycine, and phosphate buffers typically showed variation in activity compared to the family of Good buffers. beta-Galactosidase, in particular, showed greater activity with Good buffers than with phosphate or Tris buffers. Similarly, growth of seven bacterial strains was consistent, with a few exceptions, for all the Good family of buffers with Tris often inhibiting growth. Quantitation of alkaline phosphatase conjugated to antibodies is an important tool in many applications in molecular biology. Several Good buffers gave good signals when compared with Tris at pH 9.5 for detection of proteins using alkaline phosphatase-conjugated antibodies.