Abstract
Glutamate decarboxylase (GAD: EC 4.1.1.15) exists widely in animals and plants, and it is contained much specially in animal's brain and in higher plants such as squash, carrot, and tomato. We found that the activity of squash GAD was the strongest in these plants. So we investigated about various nature of squash GAD in order to transform L-glutamic acid into γ-aminobutyric acid by using squash. In this study, it was found that reaction conditions of GAD and coenzyme, pyridoxal 5'-phosphate influenced on progress of L-glutamic acid transformation in squash. We examined the reaction conditions to make the transformation enough. Consequently, we found the best range of pH value, temperature, and the amount of L-glutamic acid for entire transformation using the activity of squash GAD fully. And we established the techniques of manufacturing squash products containing much γ-aminobutyric acid from squash with L-glutamic acid, or squash with casein hydrolysate containing L-glutamic acid. Furthermore, we confirmed an effect on the blood pressure of spontaneously hypertensive rats of the products manufactured with these techniques.
