Table 1. Inductively coupled plasma mass spectrometry identifies zinc in association with PRORP.

PRORP1	Zn66 (p.p.b.)	2σ	Stoichiometry
WT	29.49	1.53	1
C344A	23.82	0.46	0.8
C347A	20.89	0.24	0.7
H548A	11.80	0.50	0.4
C565A	7.44	0.21	0.2
DD474-475AA	28.52	1.49	1
Buffer	0.44	0.12	0

Measurements were performed on wild-type PRORP1 (WT), as well as on proteins with point mutations applied to positions predicted to form the zinc-binding pocket. 2σ indicates the s.e. in four replicate measurements.