三重大学生物資源学部 三重大学生物資源学部 三重大学生物資源学部 三重大学生物資源学部 三重大学生物資源学部 Faculty of Bioresources, Mie University Faculty of Bioresources, Mie University Faculty of Bioresources, Mie University Faculty of Bioresources, Mie University Faculty of Bioresources, Mie University
三重大学生物資源学部紀要 = The bulletin of the Faculty of Bioresources, Mie University
A glutamine sensor was constructed by immobilizing L-glutaminase with glutaraldehyde on ISFET
(ion selective field effect transistor) to investigate the possibility of determining L-glutamine. The prin-
ciple of this sensor is as follows. The output voltage from ISFET, which depends on a very minute
pH elevation due to the ammonium ion formation according to the enzymic reaction, is amplified with a
differential amplifier of our own assembled. The amplified voltage was processed automatically with an
on-line personal computer via GP-IB interface on a real-time basis.
The calibration line for L-glutamine was linear from 1mM to 40mM and the relation coefficient
was 0.967. The sensitivity of this system to L-glutamine was 0.5mM. The time needed for deter-
mining one sample was within 13 min. The substrate specificity of this sensor was strict and L-
glutamine was the sole compound responding to this sensor among analogues tested. D-glutamine was
completely inactive to this sensor.
It is suggested that L-glutanrine can be determined with this newly constructed ISFET-biosensor
system with L-glutaminase.