Inactivation of the glutamic acid dehydrogenase and glucose-6-phosphate dehydrogenase enzyme-molecules in the Ehrlich ascites tumor cells of the mouse were studied. The above mentioned intracellular enzymemolecules were irradiated by the X-ray radiation under the condition of 65 kV, I Amp. under the atmosphere of nitrogen gases and by $4^{circ}C$. Thereby, irradiation doses were 580 KR/min($error:{pm}3%$). After irradiation, the cell homogentes were prepared through liquid air techniquese. There after, the activities of the enzymes were measured with photometric method given by O. Warburg and W. Christian. The dose effect curves of the activities of the two enzymes by the X-ray irradiation showed both exponential and the inactivation doses were $6,5.10^{0};and;5,0.10^{6}$ R respectively. These results showed one side that the inactivation process of the intracelluar enzymemolecules was one hit reaction after target theory, and the other side that this inactivation process could not be the primary causes of the death through X-ray irradiation of the vertebrate animals, because of the high resistance of the intracellular protein molecules against X-ray irradiation. The one hit reaction by the inactivation process of the irradiated intracellular enzymemolecules was discussed.