Biochemistry Commons^™

Hypoxanthine-Induced Differentiation Of Cultured Human Leukemia Cells, Gayle Jennette Singleton

Chemistry & Biochemistry Theses & Dissertations

Human cultured leukemia cells appear to have a decreased amount of inosine in their tRNA. When cells with inosine deficient tRNA are placed in a hypoxanthine fortified media, they incorporate hypoxanthine into their tRNA by the action of the enzyme tRNA-hypoxanthine ribosyl transferase. This generates the nucleoside inosine in the tRNA. The cultured human leukemia cell lines, CCRF-CEM, HL-60, and HGPRT(-) HL- 60, incorporate hypoxanthine into their tRNA, as determined by tRNA isolation, hydrolysis, and HPLC analysis. Hypoxanthine treatment dramatically inhibited cell growth in conjunction with partial induction of differentiation in the CCRF-CEM, HL-60, and HGPRT ( - ) HL-60 …

Evaluation Of Peptide Assimilation In Ehrlich Ascites Tumor Cells, John M. Castellano

Biological Sciences Theses & Dissertations

The dipeptides glycyl-L-(³H)-leucine and L-phenylalanyl-L-(³H)-leucine were synthesized in radioactive form and utilized in the analysis of peptide transport and hydrolysis by Ehrlich ascites tumor cells. The tumor cells were cultured in the abdominal cavity of CF-1 albino mice and harvested into sterile isotonic buffer for all experimental analyses.

The results of this study reveal that the tumor cells rapidly accumulate radiolabel when incubated with the above mentioned peptides, but that the peptide is most probably hydrolyzed extracellularly and free L-(³)-leucine transported. This hypothesis is based on the observations of reduction in accumulation of radiolabel …

The Analysis Of S-Adenosylmethionine And S-Adenosylhomocysteine In Normal And Neoplastic Cells, Kathryn Elizabeth Godburn

Chemistry & Biochemistry Theses & Dissertations

Altered patterns of methylation have been shown in both ribosomal and transfer RNA isolated from cancer cells. In contrast to the elevated activity of the methyltransferases responsible for this modification, hypomethylation appears as a general characteristic. The endogenous levels of S-adenosylmethionine and S-adenosylhomocysteine are important in relationship to their role as substrate and product of the transmethylation reaction. The levels of S-adenosylmethionine and S-adenosylhomocysteine were determined using phosphocellulose cation exchange or high pressure liquid chromatography. High voltage paper electrophoresis was used in a modified procedure to directly resolve (³⁵s) labeled S-adenosylmethionine and S-adenosylhomocysteine in small quantities of cell …