Quantification of Proline-containing Cyclic Dipeptides by LC-MS/MS.

The cyclic dipeptides, 2,5-diketopiperazines (DKPs), draw attention as bioactive and taste compounds. DKPs, especially those containing Proline (Pro), are contained in heated and fermented foods. Herein, we developed a method for a simultaneous quantitative analysis of Pro-containing DKPs using LC-MS/MS.

Investigation of the formation mechanism of proline-containing cyclic dipeptide from the linear peptide.

Cyclic dipeptides, 2,5-diketopiperazines (DKPs), are well-known bioactive and taste compounds in food. DKPs have also been reported in various foods and particularly, Pro-containing DKPs (cyclo(-X-Pro)) are more predominant in heated and fermented foods than other type of DKPs. However, the mechanism underlying the preferential formation of Pro-containing DKPs in food remains uncertain.