Prolidase.

Prolidase (EC.3.4.13.9) or proline dipeptidase, is one of the unique enzyme capable of degrading dipeptides, in which a proline or hydroxyproline residue is located at the C-terminal position. Prolidase has a unique function in all cell types; therefore, the mechanisms and parameters involved in prolidase activity regulation are of special interest. Could prolidase be a good biomarker in different physiologic and pathologic conditions? This is an important question. There is no consensus on the answer to this question. It is of great importance during collagen turnover, inflammation, tissue fibrosis and skeletal abnormalities.Prolidase itself without other biochemical markers may not provide information to clinicians about disease activity. So, I think it should be evaluated together with other serum biochemical markers.This review will serve to discuss many in vivo functions of prolidase, as well as level prolidase activity in diagnosis and monitoring of treatment in the various diseases (Ref. 50).

Increased serum nitric oxide and malondialdehyde levels in patients with acute intestinal amebiasis.

OBJECTIVE: To determine the level of oxygen-nitrogen stress parameters in the pathogenesis of amebiasis. METHODS: Twenty-four acute intestinal amebiasis patients and 20 healthy controls were enrolled in the present study. Serum malondialdehyde and nitric oxide levels were determined spectrophotometrically. RESULTS: Serum malondialdehyde and nitric oxide levels were significantly higher in acute intestinal amebiasis patients than healthy controls (P<0.001). CONCLUSIONS: These results suggest that oxidative and nitrosative stress may play a major role in tissue damage in acute intestinal amebiasis patients. Also these parameters can be used to supplement the conventional microscopic method for reliable diagnosis of intestinal amebiasis.

Evaluation of oxidative and nitrosative stress in hemodialysis patients.

AIM: Oxidative/nitrosative stress has long been demonstrated in hemodialysis patients. It is associated with numerous complications such as atherosclerosis and related cardiovascular disturbances. However, the factors influencing oxidative/nitrosative status have not been characterized extensively in these patients. Therefore, the present study was designed to investigate the alteration of oxidative/nitrosative stress parameters and total antioxidant status. METHODS: Forty-one hemodialysis patients and 41 healthy subjects were enrolled in the present study. Serum myeloperoxidase, nitrotyrosine and total antioxidant capacity were determined. RESULTS: Serum myeloperoxidase and nitrotyrosine were significantly higher in the haemodialysis patients compared to the healthy subjects (P<0.05) while total antioxidant capacity was lower (P<0.01). CONCLUSION: According to the results of this study, oxidative and nitrosative stress is increased in haemodialysis patients, therefore these alterations should be considered in the treatment of these patients.

Serum prolidase activity in postmenopausal osteoporosis.

AIM: Prolidase is a specific imidodipeptidase involved in collagen degradation. The increase in the enzyme activity is believed to be correlated with increased intensity of collagen degradation and may be a useful tool in diagnosis and/or monitoring osteoporosis. The study aimed to evaluate serum prolidase activity in postmenopausal osteoporosis and its relation with several metabolic bone markers. METHODS: Sixty-one postmenopausal women with menopause times = or >1 year without any hormone replacement treatment were recruited in this study. Bone mineral density (BMD) was obtained from antero-posterior spine L2-L4 and femoral neck scanning with dual energy X-ray absorptiometry (DXA). Thirty-one subjects with T scores lower than -2.5 were accepted as osteoporotic and control group consisted of 30 subjects. Urinary deoxypyridinoline (Dpd), calcium, creatinine, serum total calcium, phosphorus (Pi), alkaline phosphatase, parathyroid hormone levels and prolidase activity were analysed with colorimetric or immunochemical RESULTS: Serum prolidase activity was neither significantly different in osteoporosis nor correlate with other bone turnover markers. Urinary Dpd/creatinine and serum Pi levels of postmenopausal osteoporotic group were significantly higher than in the control group. CONCLUSION: Serum prolidase activity does not correlate with BMD in postmenopausal osteoporosis with menopause time over 1 year. However, its role during premenopausal accelerated decrease in BMD is not established yet.

A study of prolidase in mothers, their newborn babies and in non-pregnant controls.

The prolidase activity in serum and in erythrocytes was measured in 28 healthy mothers and in the cord blood of their newborn babies in using a modified Chinard method. 45 healthy non-pregnant women aged between 15-36 years formed a control group. Biochemical parameters (CK, BUN, C-peptid, AFP, Uric acid) were also measured. The serum and erythrocyte prolidase activities in maternal blood were 45.8+/-13.4 U/L and 37.8+/-2.7 U/g Hb respectively. There was no significant difference in the enzyme activities between pregnant women and the control group (p>0.05). However serum and erythrocyte prolidase activity in cord blood (20.3+/-8.2 U/L and 31.6+/-7.3 U/g Hb) was significantly different when compared with control group (53.4+/-14.7 U/L in serum and 42.3+/-10.3 U/g Hb in erythrocyte, p<0.001). There was a significant correlation between maternal and cord blood serum enzyme activity (r: 0.76 p<0.01). This correlation was also shown in erythrocyte prolidase activities of both groups (r: 0.49, p<0.05). Cord blood prolidase activity was positively correlated with birth weight (r: 0.89, p<0.01). Prolidase activity in cord blood was low even though collagen turnover is increased in fetal growth.