Variations in sulfhydryl, disulfide, and protein content during synchronous and asynchronous growth of HeLa cells.
The cellular contents of protein-bound and nonprotein sulfhydry (-SH) and disulfide (-SS-) groups were measured in both asynchronous and synchronous HeLa S3 cultures. About 90% of these groups are associated with proteins, the majority in the -SH form. The content of protein-bound groups, and hence the total content of -SH and -SS- groups (28 x 10(-15) moles/cell, or 1.1 x 10(-6) moles/g protein on average), changes in parallel with the protein content (which varies between 2 and 4 x 10(-10) g/cell) as asynchronous populations pass from the lag through the exponential to the stationary phase of growth. The concentration of nonprotein -SH groups, in contrast, increases 10-fold during lag phase and decreases in stationary phase; it follows the protein concentration closely during the exponential phase, at a level of about 2.8 x 10(-15) moles/cell. In synchronous cultures the protein content doubles during the cell cycle, possibly in an exponential fashion. The total -SH and -SS- content also doubles, but the rate of increase appears to fluctuate. The concentrations of the protein-bound groups show 2- to 3-fold fluctuations per unit protein: protein-bound -SH groups and mixed -SS- linkages rise to maxima while protein-bound -SS- groups fall to a minimum at the G(1)/S transition, and fluctuations in these groups occur again during G(2). In addition, the protein-bound -SH concentration falls continuously during the S phase. The nonprotein -SH concentration undergoes the largest (relative) fluctuations, dropping from 4 x 10(-15)moles/cell in early G(1) to about 0.4 x 10(-15) moles/cell (of standard protein content) at the end of G(1), and then rising to 30 times this value by the end of S.
D001120:Arginine / Q000378:metabolism; D002247:Carbon Isotopes; D055598:Chemical Phenomena; D002621:Chemistry; D003470:Culture Media; D046508:Culture Techniques; D004273:DNA, Neoplasm / Q000096:biosynthesis; D006367:HeLa Cells / Q000254:growth & development / Q000378:metabolism*; D008722:Methods; D008938:Mitosis; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000378:metabolism*; D010507:Periodicity; D013438:Sulfhydryl Compounds / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D013440:Sulfides / Q000096:biosynthesis / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014633:Valine / Q000378:metabolism
D002247:Carbon Isotopes; D003470:Culture Media; D004273:DNA, Neoplasm; D009363:Neoplasm Proteins; D013438:Sulfhydryl Compounds; D013440:Sulfides; D001120:Arginine; D014633:Valine; D013936:Thymidine