Hydrolysis of proline dipeptides completely fulfills the proline requirement in a proline-auxotrophic Chinese hamster ovary cell line.
Proline- and hydroxyproline-containing oligopeptides may be important in protein nutrition because intestinal hydrolases are incapable of recognizing their imido bonds. Peripheral tissues have a cytosolic enzyme prolidase that cleaves dipeptides containing C-terminal proline (X-Pro) or hydroxyproline. The role of dipeptides in intracellular metabolism is uncertain. This study examined the ability of X-Pro to provide proline to the proline-auxotrophic cell line, CHO-K1. The action of prolidase on exogenously supplied Gly-Pro, the most abundant dipeptide product of digestion, provided adequate proline to support normal cell growth of CHO-K1 cells in a dose-dependent manner. The growth curve generated by addition of Gly-Pro to CHO-K1 cells was similar to that due to proline. Two other structurally unrelated X-Pro also supported growth indistinguishably from Gly-Pro. Gly-Hyp was completely ineffective for growth. The ability of X-Pro to sustain cultures of a proline-auxotrophic cell line may be important in elucidating intracellular nutritional and physiological functions for those dipeptides.
Emmerson
K S
KS
Laboratory of Nutritional and Molecular Regulation, National Cancer Institute, Frederick Cancer Research and Development Center, MD 21702.
Phang
J M
JM
D000818:Animals; D016466:CHO Cells; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D004150:Dipeptidases / Q000502:physiology*; D004151:Dipeptides / Q000378:metabolism; D006868:Hydrolysis; D009751:Nutritional Requirements; D011392:Proline / Q000378:metabolism* / Q000494:pharmacology
D004151:Dipeptides; D011392:Proline; D004150:Dipeptidases; C022449:proline dipeptidase