Abstract
A study to investigate the ability of liver to synthesize serum γ-globulin has been made by the detection of its net production with an application of the quantitative precipitin reaction. The following results have been obtained:
1. The liver slice, when incubated in a medium of salt mixture, could produce 136±7.6μg. of γ-globulin in 2 hours per g. of wet weight of liver. This net production was enhanced by using acid hydrolysates of plasma proteins as a medium and markedly reduced by adding several metabolic inhibitors to the medium.
2. The homogenate could not reproduce this activity under the same condition as in the case of the slice, but it was almost recovered by fortifi-cation with ATP at a final concentration of 3.5×10-3M.
3. With use of various subcellular fractions prepared by differential centrifugation, it was demonstrated that the microsomes, in combination of the supernatant fraction, retained about 70 per cent of the activity compared to the whole homogenate, and the particulate fractions alone showed no detectable net production.
4. In the deoxycholate soluble system which consisted of the deoxycholate soluble components derived from the particulate fractions, TCA or PCA soluble factors of the supernatant fraction and ATP, authors have demonstrated the net production of γ-globulin, though to a limited extent.
5. In this soluble system, active proteins in deoxycholate extracts were able to be salted out with between 10 and 20 g./dl. of ammonium sulfate solution, and RNase inhibitors, although unknown, were indicated as one of the important factors involved in the deproteinized supernatant. Compared to ATP, GTP was found more efficient.
The authors wish to express their heartful gratitude to Prof. N. Shimazon o and Associate Prof. H. Hirai for their continuous encouragements and interest during the course of this work. Their thanks are also due to Mrs. S. B. Blume for her kind advices to complete this mamuscript.
