Response-surface-optimized, zinc-enhanced assay for serum alkaline phosphatase.

Abstract

An optimized assay for alkaline phosphatase (EC 3.1.3.1) is reported. A discrete analyzer, the DuPont Automatic Clinical Analyzer (aca), was used for this study. The assay is based on results of response-surface experimental co-optimization techniques, and response is enhanced over the present aca assay. A key feature is the incorporation of zinc ions, both to fully optimize the assay and to reduce the sensitivity of measured activity to zinc-binding impurities in the buffer, 2-amino-2-methyl-1-propanol. In addition, a simple technique is described for measuring relative concentrations of zinc-binding impurities in this buffer. These features should be considered in the design of any assay for alkaline phosphatase that is based on p-nitrophenyl phosphate as substrate and 2-amino-2-methyl-1-propanol as buffer.

Response Surface Methodology

“…They point out that such an approach permits the determination of accurate optima which is required for the formulation of analytically reliablc clinical methods. Thompson et al (1981) report on the use of simultancous RSM optimization tcchniques to optimize an as.say for alkaline phosphatase. London et al (1982)• use RSM to optimize the assay of gamma-glutamyltransferase.…”