Abstract
The physicochemical properties of Saliva-parotin-A were investigated. It gave a positive reaction to all coloring and precipitating reactions of protein.
It had an isoelectric point of pH 5.4-5.6, but did not precipitate at that pH.
Purity by electrophoresis was shown to be 90%(by ascending pattern), but by ultracentrifugal analysis a single boundary was obtained.
Ultraviolet absorption maximum was at 277.5±0.5mμ and the polarogram in the presence of Co++or Co+++did not produce a protein wave.
The total nitrogen was 15.21%. It did not contain sulphur and ash. It consisted of 15 kinds of amino acids with the exception of sulphur containing amino acids.
As to the biological properties of Saliva-parotin-A, the minimum effective dose for rabbit serum calcium decreasing activity was 50 to 100μg; for circulating leucocytes decreasing and increasing activity 5 to 10μg; for calcification of rabbit incisor dentine 10μg.
Saliva-parotin-A is a different kind of protein from Parotin so far as the physicochemical properties are concerned.
