- Erythrocyte glutamic-pyruvic transaminase (EGPT) and
glutamic-oxaloacetic transaminase (EGOT) activities reflect
vitamin B₆ status in humans (Baysal, Johnson, and Linkswiler,
1966). Pyridoxal phosphate (PALPO), an active form
of vitamin B₆, serves as the coenzyme for these transaminases.
Compared to other methods of vitamin B₆ assessment,
transaminase measurement has the advantage of dealing with
a single enzyme requiring PALPO and reflecting the subject's
vitamin B₆ status over a long period of time (Sauberlich
et al., 1970).
Although studies on transaminase activity in adults
have been reported, information on EGPT and EGOT activities
in children is not available. This study was undertaken
to determine the activities of EGPT and EGOT in normal preschool,
children. In addition, factors affecting transaminase
activities were considered. The storage stability of
EGPT and EGOT was also reported.
Participating in this study were 109 subjects, aged
from 21 to 126 months. The activities of EGPT and EGOT were
expressed as μg pyruvate/mg hemoglobin (Hb)/hr and mg pyruvate/
ml red blood cells/hr. The basal activity indicates
the level of holoenzyme. The stimulated activity with
added in-vitro PALPO shows the level of holoenzyme plus apoenzyme.
The percent stimulation represents the degree of
saturation of apoenzyme with the coenzyme (Cavill and
For EGPT, the basal activity and percent stimulation
were 1.20 ± 0.44 μg pyruvate/mg Hb/hr and 11.70 ± 7.00 percent,
respectively. Those of EGOT were 23.30 ± 5.77 μg pyruvate/
mg Hb/hr and 69.90 ± 23.3 percent. The two different
ways of expressing basal activity of EGPT and EGOT were
highly correlated with one another.
A significant positive correlation was found between
the basal activities of EGPT and EGOT (p < 0.01). However,
the positive relationship between their corresponding percent
stimulation was> not significant. The stimulated and
basal activities for both EGPT and EGOT were closely correlated
(p < 0.01), which indicated that the level of holoenzyme
is largely dependent on the amount of-apoenzyme
available. A significant inverse relationship (p < 0.01)
existed between the basal activity and percent stimulation
of EGOT, which meant that the high enzyme activity level is
usually associated with a high degree of saturation of the apoenzyme with PALPO. The similar inverse relationship for
EGPT was not statistically significant.
In the subjects whose diet was supplemented with multivitamins
containing pyridoxine, the transaminase activities
appeared to be higher and the corresponding percent stimulation
lower than in those receiving no supplementation.
However, the difference was only significant for basal EGPT,
using the Student's t test (p < 0.01).
The subjects with high basal activities or low percent
stimulation of EGPT or EGOT also tended to have higher
plasma vitamin B₆ levels. But these relationships were not
As the age of the subjects increased, the basal and
stimulated activities of both EGPT and EGOT declined, accompanied
by the corresponding increase in percent stimulation.
The correlations for basal and stimulated activities,
as well as percent stimulation of EGOT, but not EGPT, with
age were significant (p < 0.05).
The differences in transaminase activities due to sex
were not significant. But in general, the girls had a
lower basal activity and a higher percent stimulation for
both EGPT and EGOT than the boys.
The average hemoglobin level of the subjects was
12.95 ± 0.77 g percent. The hemoglobin levels increased
significantly with age (p < 0.01).
Finally, experiments with two hemolysate samples
showed that no loss of EGPT or EGOT activities occurred
with freezing and storage within 13 days.