Influence of two glutamine-containing dipeptides on growth of mammalian cells.

The instability of the amino acid glutamine prompted us to investigate substitute compounds appropriate for culture conditions. The effect of two glutamine-containing dipeptides, alanylglutamine (Ala-Gln) and glycylglutamine (Gly-Gln), on the growth behavior of a hematopoietic cell line in culture (K562) was investigated. Growth rates and [3H]thymidine incorporation rates of cells cultivated in sterile-filtrated media, containing glutamine (Gln) or Ala-Gln or Gly-Gln, were not statistically different. Although heart-sterilization of media containing Gln caused approximately 95% decomposition of the Gln, both dipeptides remained unaltered. Consequently, cell growth was drastically decreased when autoclaved free Gln-containing media were used, but growth was unaffected in the presence of autoclaved dipeptides. Both Ala-Gln and Gly-Gln have an advantage over free Gln as growth factors for cell culture due to the stability of the dipeptides during both autoclaving and storage; the biological activity, however, is comparable.