Products

Specialty Assays manufactures and sells a variety of NAD and NADP analogs. These analogs in both their oxidized and reduced states exhibit several chemical and physical properties which makes them advantageous to use in certain situations compared with NAD and NADP. In their oxidized state they have higher oxidation potentials than NAD and NADP, and thus enzymatic oxidations that proceed with difficulty with NAD and NADP proceed more easily with the corresponding analogs. In their reduced states the analogs are considerably more stable at acid, neutral, and slightly alkaline pH values, which results in significantly greater aqueous stabilities than with NADH and NADPH. The reduced forms also have significant absorbances in the visible region of the spectrum and much higher molar absorptivities than NADH and NADPH.

Specialty Assays has recently synthesized and developed assays for Calcium, Magnesium, and Sodium using Phosphonazo III. Phosphonazo III is the phosphorousanalog of Arsenazo III, where the two Arsenic molecules have been replaced with two phosphorous molecules.

For calcium measurements, phosphonazo III offers several advantages over currentmethods, which use arsenazo III and ortho-cresolphthalein complexone (CPC). Compared with arsenazo III, phosphonazo III is about 38% more sensitive and poses no environmental waste concerns since it contains no arsenic. Compared with CPC methods phosphonazo III is about 300% more sensitive and unlike CPC methods,which require a pH of ~11.7 to bind calcium, phosphonazo III binds best at a slightly acidic pH, ~5.5. Therefore phosphonazo III reagent stability is not affected by ambient carbon dioxide, which over time lowers the pH of CPC methods, making the reagents unusable for calcium determinations. Also, the phosphonazo III-calcium complex has two absorbance maxima in the visible region of the spectrum at 600 and 650 nm,compared with CPC methods where the CPC-Ca complex absorbs around 578 nm. The longer wavelengths of phosphonazo III are much less prone to sample spectral interferences, especially those found in biological specimens.