Comparisons were made of the rate of incorporation of C14-labeled l-amino acids into protein of chicken embryo chorioallantoic membrane (CAM) infected with viruses that induce cell proliferation. A tumor virus (Rous sarcoma virus) and a nontumor virus (fowl pox virus) were used in these studies. In ovo studies of glycine-C14 incorporation into the protein of Rous sarcoma virus-induced tumors showed a progressive increase in protein specific activity from the 3d to the 6th day following infection of the CAM of 10-day-old embryos, whereas uninfected CAM yielded a marked decrease in activity during the same time period. In vitro incubation of tissue slices with C14-labeled glycine, glutamate, and leucine showed a one- to twofold increase in amino acid incorporation into protein of Rous tumors and fowl pox hyperplasia when compared with uninfected (control) CAM from embryos of the same age. Comparisons of fractions from cell-free homogenates showed the pH-5 enzyme-microsome system of Rous tumors to have a three- to fourfold increase in amino acid incorporation into protein over that observed with similar preparations from CAM or fowl pox virusinfected tissues. Species specificity of the pH-5 enzymes was observed. Rous tumor pH-5 enzymes increased the amino acid incorporation activity of CAM and chick embryo liver microsomes but were ineffective when combined with rat liver microsomes.


Supported by grants-in-aid from U.S.P.H.S. Grant Numbers C-06276 and CA-04692.

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