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Purification of meprin from human kidney and its role in parathyroid hormone degradation
T Yamaguchi1, M Fukase, T Sugimoto
1Department of Medicine, Kobe University School of Medicine, Japan.
Abstract:
Meprin (EC 3.4.24.18) is known to occur in the kidneys of mice and rats, but has not previously been found in human kidneys. Here we report the isolation of meprin from human kidney and show that it has a role in the degradation of parathyroid hormone (PTH) in that organ. The purified human meprin had properties almost identical to those of rat meprin including molecular size, substrate specificity and inhibitor sensitivity, and it also cross-reacted well with an antibody raised against rat meprin. Both the purified human meprin and the microvillar membranes of human kidney readily hydrolyzed human parathyroid hormone [hPTH-(1-84)] into several fragments, whose amino acid sequences corresponded well to each other. Thus, meprin appears to play a major role in the PTH-degrading activity in the microvillar membranes of human kidney. Our results indicate that meprin, which so far has mainly been investigated in mice and rats, is found not only in these rodents, but also in the human kidney, and suggest that its physiological role in humans is to degrade PTH in the kidney.
Insights
Researchers discovered meprin in human kidneys, an enzyme previously found only in rodents. This enzyme plays a key role in breaking down parathyroid hormone (PTH) within the human kidney.
Area of Science:
- Biochemistry
- Nephrology
- Enzymology
Background:
- Meprin (EC 3.4.24.18) is an enzyme primarily studied in rodent kidneys.
- Its presence and function in human kidneys have not been previously established.
Purpose of the Study:
- To isolate and characterize meprin from human kidney tissue.
- To investigate the role of human kidney meprin in the degradation of parathyroid hormone (PTH).
Main Methods:
- Isolation and purification of meprin from human kidney.
- Biochemical characterization of human meprin, including molecular size, substrate specificity, and inhibitor sensitivity.
- Assay of human meprin and kidney microvillar membranes for parathyroid hormone degrading activity.
Main Results:
- Human kidney meprin was successfully isolated and exhibited properties similar to rat meprin.
- Human meprin and human kidney microvillar membranes effectively hydrolyzed human parathyroid hormone [hPTH-(1-84)] into multiple fragments.
- Human meprin demonstrated cross-reactivity with antibodies raised against rat meprin.
Conclusions:
- Meprin is present in the human kidney and shares characteristics with its rodent counterparts.
- Meprin plays a significant role in the degradation of parathyroid hormone within the human kidney's microvillar membranes.
- This finding suggests a conserved physiological role for meprin in PTH metabolism across species.