Table 1. Sample details.

	RNaseA	Lysozyme	Xylanase	Urate oxidase	Xylose isomerase
Organism	Bos taurus (pancreas)	Gallus gallus (hen egg white)	Trichoderma reesei	Aspergillus flavus	Streptomyces rubiginosus
Source (catalogue No. or reference)	Sigma–Aldrich R6513	Sigma–Aldrich L6876 or L4919	Hampton Research HR7-104	Sanofi–Aventis, Pichia pastoris expression	Hampton Research HR7-102
Description: UniProt ID (sequence range in construct)	P61823 (27–150)	P00698 (19–147)	F8W669 (1–190)	Q00511 (2–302) with acetylated N-terminal Ser and 8-azaxanthine inhibitor: C4H3N5O2	P24300 (1–388)
Calculated extinction coefficient ɛ, A 280 0.1%
From sequence†	0.69	2.65	2.80	1.56	1.07
8-Azaxanthine‡				0.28
Sequence + xanthine				1.84
Calculated partial specific volume § (cm3 g−1, 20°C)	0.710	0.716	0.712	0.735	0.727
Mean protein and solvent scattering length densities¶ (1010 cm−2)	12.621, 9.469	12.507, 9.484	12.518, 9.469	12.360, 9.489	12.363, 9.470
Mean scattering contrast¶ (1010 cm−2)	3.151	3.023	3.049	2.871	2.893
Molecular mass from chemical composition† (Da)	13690.3 (monomer)	14313.1 (monomer)	20843.6 (monomer)	34150.7 (protomer), 136603 (tetramer)	43227.4 (protomer), 172910 (tetramer)
Molecular mass from mass spectrometry†† (Da)	—	—	20825.0	34151.4 (protomer)	43227.6 (protomer)
Standard solvent composition	50 mM Tris pH 7.5, 100 mM NaCl	50 mM sodium citrate pH 4.5, 150 mM NaCl	50 mM Tris pH 7.5, 100 mM NaCl	100 mM Tris pH 8.0, 150 mM NaCl	50 mM Tris pH 7.5, 100 mM NaCl, 1 mM MgCl2

^†Calculated using ProtParam (Gasteiger et al., 2005 ▸).

^‡Experimentally determined.

^§Calculated using SEDNTERP (Philo, 1997 ▸); see also Section S2 and Supplementary Table S2.

^¶Calculated using MULCh (Whitten et al., 2008 ▸).

^††Performed at Sydney Mass Spectrometry. Note: urate oxidase shows a second resolved peak at 34 169 Da.