Polymorphism in fowl serum albumin. VII. Distribution and activity of free and membrane-bound polysomes in developing fowl liver.
The quantity and activities of membrane-bound and free polysomes in livers from chick embryos at successive stages of development were compared in cell-free protein-synthesizing systems. Membrane-bound polysomes increased 2-fold between 8 and 18 days of development, while total ribosome content remained constant. Free polysome activity also remained constant during this period, while that of membrane-bound (total--free) polysomes decreased, possibly because of an increase in ribonuclease activity in this fraction. Serum albumin biosynthesis occurred primarily on membrane-bound polysomes. With liver development, increased secretion of serum proteins may be correlated with synthesis of serum albumin on increasing numbers of membrane bound polyribosomes.
D000418:Albumins / Q000096:biosynthesis*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002474:Cell-Free System; D002642:Chick Embryo; D008099:Liver / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D013997:Time Factors
D000418:Albumins; D012260:Ribonucleases; D008239:Lysine