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Science 19 December 1969:
Vol. 166. no. 3912, pp. 1536 - 1538
DOI: 10.1126/science.166.3912.1536
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Articles

Temporal Coordination of DNA Replication with Enzyme Synthesis in Diploid and Heteroploid Cells

Robert R. Klevecz 1

1 Department of Biology, City of Hope Medical Center, Duarte, California 91010

The rate of DNA synthesis in the S phase of growth of synchronized diploid Chinese hamster cells shows two maximums, while in heteroploid hamster cells the DNA replication rate is constant. In diploid cells a reciprocal relationship exists between maximum DNA synthetic rates and maximum lactate dyhydrogenase and thymidine kinase enzyme levels. Enzyme activity in heteroploid cells increases continuously through the cell cycle with no evidence of oscillations. It seems possible that these differences in molecular organization may accompany or precede the transition to heteroploidy.

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Science. ISSN 0036-8075 (print), 1095-9203 (online)