Measurement of Iminodipeptides in the Serum of Patients with Prolidase Deficiency Using Liquid Chromatography-Mass Spectrometry

Abstract

Iminodipeptides containing C-terminal proline or hydroxyproline were determined in sera from patients with prolidase deficiency, in their mother's serum, and in the sera of unfelated controls, using liquid chromatography-mass Spectrometry with an atmospheric pressure ionization interface System. The Separation was carried out on a reversed phase column using l g/l aqueous trifluoroacetic acid-methanol (75 + 25, by vol.). The quasi-molecular ions ([M -l· H])" 1 " of various Iminodipeptides containing C-terminal proline and hydroxyproline were observed in the sera of patients with prolidase deficiency, using selected ipn monitoring. The quasi-molecular ions ([M + H]) + of iminodipeptides containing C-terminal proline were not observed in the sera of normal subjects or the patients' mother, but the latter did contain various iminodipeptides with C-terminal hydroxyproline. This method proved usefiil for the determination of iminodipeptides in the sera of patients with prolidase deficiency.

The role of emerging techniques in the investigation of prolidase deficiency: From diagnosis to the development of a possible therapeutical approach

“…Although it was never used for diagnostic purposes on urine of PD patients, this method was further improved by Sugahara et al [38] to measure simultaneously both imidodipeptides containing N-or C-terminal proline. The HPLC-API/MS method above indicated was applied by Sugahara et al [39] also on serum of both normal subjects and PD patients. If the [M + H] + ions of imidodipeptides containing C-terminal proline were not observed in the sera of controls, they were identified in those of PD patients thus indicating that this could be a useful tool for the diagnosis of the disorder.…”

Determination of prolidase activity using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

“…Several assays that detect dipeptide in urine have been described for the detection of prolidase deWciency [24][25][26]. In addition, some assays have been used to detect dipeptides in human serum/plasma [27][28][29].…”

Corticosteroid treatment of prolidase deficiency skin lesions by inhibiting iminodipeptide-primed neutrophil superoxide generation

“…Patient 2 showed higher neutrophil superoxide generation than patient 1, while the serum iminodipeptide levels were similar in both patients. 10 This discrepancy raises the possibility that the differences in the severity of skin lesions and mental retardation between the two patients may have been related to the relative superoxide‐generating activity of PMN.…”

“…Serum iminodipeptide levels were assayed as described previously. 8 , 10 Briefly, a mixture of 2 mL serum and 6 mL 2% sulphosalicylic acid was stirred and centrifuged at 1000 g for 10 min. The supernatant was transferred to a column containing 10 mL of Diaion SK‐I (H + form, 100 mesh, Mitsubishi Kasei, Tokyo, Japan) and washed with 50 mL of water.…”

“… 1–6 The two sisters presented here excreted large amounts of iminodipeptides in their urine, 7 , 8 had deficient prolidase activity of red blood cells, 9 and had elevated serum iminodipeptide levels. 10 Impaired healing of leg ulcers has been attributed to defective recycling of proline from iminodipeptides. 11 Oral l ‐proline (4, 12 6 4 and 10 g/day 2 ) has, however, not been clearly beneficial.…”