The homogenate was centrifuged at 1,500 g for 5 min, and TNAP activity in the supernatant was measured using p-nitrophenyl phosphate pNPP as substrate at pH 10.4 and recording the absorbance of nitrophenolate at 405nm (ԑ is equal to 18.8 mM -1 cm -1 ) [35 ].
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