Therapeutic use of the SMR1 protein and active derivatives thereof

A method for treating a disorder affecting the bone in a mammal, comprising administering to the mammal a pharmaceutically active amount of:

• (A) an SMR1 protein comprising SEQ ID NO:
• 14,
• (B) a fragment of the SMR1 protein comprising SEQ ID NO:
• 14,
• (C) a maturation product of the SMR1 protein comprising SEQ ID NO:1, SEQ ID NO:7 or SEQ ID NO:12, or
• (D) a derivative of the SMR1 protein of(A), the fragment of(B) or the maturation product of (C) that comprises at least one modified amino acid residue, which has improved stability and which retains the mineral imbalance modulating activity of the protein of (A), the fragment of (B) or the maturation product of (C), and wherein said protein, fragment, maturation product or derivative modulates mineral ion concentration.

A method for determining the amount of SMR1 protein, fragment, maturation product or derivative thereof to be administered to a patient suffering from a metabolic imbalance or a mineral ion imbalance, wherein

• (A) the SMR1 protein comprises SEQ ID NO:14,
• (B) the fragment of the SMR1 protein comprises SEQ ID NO:14,
• (C) the maturation product of the SMR1 protein comprises SEQ ID NO:1, SEQ ID NO:7 or SEQ ID NO:12, and
• (D) the derivative of the SMR1 protein of (A), the fragment of (B) or the maturation product of (C) has at least one modified amino acid residue for improved stability and which retains the mineral imbalance modulating activity of the protein of (A), the fragment of (B) or the maturation product of (C), and wherein said protein, fragment, maturation product or derivative modulates mineral ion concentration, the method comprising:
• a) incubating a labeled peptide comprising XQHNPR (SEQ ID NO:14) with a polyclonal or a monoclonal antibody directed against the peptide to form an immune complex;
• b) contacting said immune complex with a biological sample from a patient to be tested, wherein said sample is suspected to contain an endogenous non-labeled peptide comprising XQHNPR (SEQ ID NO:14);
• c) detecting the amount of monoclonal or polyclonal antibody-bound labeled peptides that have not been displaced by the non-labeled endogenous peptide comprising XQHNPR (SEQ ID NO:14) contained in the biological sample, thus determining the concentration of the endogenous peptide in the sample;
• d) comparing the concentration of the peptide comprising XQHNPR (SEQ ID NO:14) in the biological sample from the patient with the concentration of the peptide comprising XQHNPR (SEQ ID NO:14) normally found in a healthy individual;
• and
• e) calculating the amount of SMR1 protein, fragment, maturation product or derivative necessary to supply the defect in the SMR1 protein or maturation factor in body fluids or tissues of said patient.