Summary
The modified amino acid y-carboxyglutamic acid (Gla) occurs in several proteins such as prothrombin, blood coagulation factors VII, IX and X, proteins C, S and Z as well as matrix Gla protein and osteocalcin. The amount of Gla excreted in urine is a common indicator of the whole-body degradation of these proteins. We have determined the renal excretion rates of Gla in 3, 6,10,14 and 18 years old male and female human subjects (n = 14 per age group and sex) and calculated the respective resting metabolic rates (RMR) on the basis of the body weights using published formulas. We found high correlations between the excretion rates of Gla (µmol/d/kg body weight) and the RMR (kJ/d/kg body weight) in the females (n = 70) of r = 0.70 (y = 0.003x + 0.29) and in the males (n = 70) of r = 0.70 (y = 0.0038x + 0.27) and in all subjects (n = 140) of r = 0.69 (y = 0.0035x + 0.27); p < 0.01. We postulate that in children and adolescents a causal relationship exists between the whole-body degradation rate of Gla containing proteins and the metabolic rate.
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Topp, H., Iontcheva, V. & Schöch, G. Renal excretion ofγ-carboxyglutamic acid and metabolic rate in 3–18 years old humans. Amino Acids 14, 371–377 (1998). https://doi.org/10.1007/BF01318856
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DOI: https://doi.org/10.1007/BF01318856