Evidence for the Participation of a 5-Oxo-prolinase in Degradation of Glutathione in Nicotiana tabacum

Abstract

During degradation of glutathione in tobacco suspension cultures substancial amounts of 5-oxo-proline are formed in vivo as well as in crude cell homogenates in vitro. The existance of a 5-oxo-prolinase that catalyzes the conversion of 5-oxo-proline to glutamic acid was demonstrated in tobacco cells, grown with glutathione as sole sulfur source.