Printed in Great Britain QUANTITATIVE INVESTIGATION ON THE EFFECT OF PUROMYCIN ON THE AGGREGATION OF TRYPSIN- AND

Embryonic chick fibroblast cells were used to test the effects of puromycin on cell adhesion and aggregation. Single cell suspensions were prepared by dissociating the muscle tissues of 5- and 9-day-old chick embryos with either trypsin or versene according to standard cell dis-sociation procedures. ' Cell aggregation was quantitatively estimated by a turbidimetric method. Quantitative analyses of the components in cell-free supernatants revealed that both trypsin and versene when used as cell dissociating agents removed substantial amounts of protein from the surfaces of the cells and the intercellular regions. Trypsin removed larger quantities of protein and of iV-acetylneuraminic acid than did versene. Nucleic acids were also released during trypsin and versene dissociation, and estimations of these nucleic acids gave a measure of the extent of cell lysis. The proteins and peptides were separated by gel filtration. The solubilized proteins removed by versene treatment were separated into three peaks on Sephadex G.200. The tryptic digest gave one main peptide peak on Sephadex G.50. Both trypsin- and versene-dissociated cells, on rotation in Hanks's balanced salts solution with or without serum, began to adhere to one another at the start of the test period, indicating that the cell dissociation procedures had not impaired the adhesive properties of the separate