Biochemical characteristics of
gustin, the major
zinc protein in human parotid saliva, are similar whether the
protein is isolated from subjects with normal taste acuity or from patients with
hypogeusia (who may have a little as 1/5th as much parotid saliva
gustin as normal subjects do).
Zinc concentration in fraction II of parotid saliva, the fraction in which
gustin is found on
Sephadex G-150 or
Sephacryl S-200 column chromatography, is proportional to the
gustin content of saliva and is decreased in patients with lower than normal total parotid saliva
zinc. The quantity and spectrophotometric indices of all other
protein fractions isolated from patients by these column chromatographic techniques did not differ from those of normals. One patient with proven
hypogeusia and low concentrations of
zinc in total parotid saliva and fraction II, after 9 days of treatment with exogenous
zinc, showed a 150% increase in fraction II
zinc and a concomitant increase in apparent
gustin levels; these changes preceded the return of normal taste function. These data demonstrate that
zinc treatment can affect both taste and
gustin concentrations in
hypogeusia.