Functional Analysis of Thyroid Peroxidase Gene Mutations Detected in Patients with Thyroid Dyshormonogenesis

Table 5

Guaiacol and iodide oxidation activity of expressed human TPO protein.

Mutation	Guaiacol oxidation	Iodide oxidation
Wild type	0.76±0.07	0.90±0.05
Glu 641 Lys	ND	*
Asp 668 Asn	0.63±0.07	0.69±0.27
Thr 725 Pro	ND	*
Asp 620 Asn	ND	*
Ser 398 Thr	0.70±0.27	0.82±0.29
Ala 373 Ser	0.62±0.09	*

Enzyme activity was activity expressed as Δ𝐴·min⁻¹·mg protein⁻¹.
*Comparable with nonenzymatic reaction rate (0.51±0.24). ND: no detectable activity (<10% of wild-type expressed TPO) [5].