Human Serum Amyloid P Component is a Single Uncomplexed Pentamer in Whole Serum

Table 1 FPLC gel filtration of human SAP and CRP on Superose 12HR

Sample	Eluant	V_e (ml)	Oligomerization State
Isolated SAP	TE buffer pH 8.0	10.7	decamer
Isolated CRP	TE buffer pH 8.0	11.7	pentamer
Isolated SAP	Tris/borate pH 8.4	10.1	decamer
Isolated CRP	Tris/borate pH 8.4	12.6	pentamer
Isolated SAP	Tris/carbonate pH 8.4	10.4	decamer
Isolated CRP	Tris/carbonate pH 8.4	11.7	pentamer
Isolated SAP	Triethanolamine pH 8.4	11.2	decamer
Isolated CRP	Triethanolamine pH 8.4	12.9	pentamer
Isolated SAP	PBS	10.8	decamer
Isolated CRP	PBS	11.7	pentamer
Isolated SAP	Tris/phosphate pH 6.4, 7.4 or 8.4	11.7	pentamer
Isolated CRP	Tris/phosphate pH 6.4, 7.4 or 8.4	11.8	pentamer
SAP + MOβDG/Ca⁺⁺	TN buffer + Ca⁺⁺	11.5	pentamer
SAP + dAMP/Ca⁺⁺	TN buffer + Ca⁺⁺	10.9	decamer
SAP in whole serum	TE buffer	11.4	decamer
CRP in whole serum	TE buffer	12.2	pentamer

Details of buffer composition in “Materials and Methods” and Results. Experiments were performed in the pairs shown. Differences in absolute elution volume (V_e) values between pairs reflect buffer effects and drift in column performance with time, multiple runs (including whole serum samples) and multiple cleaning cycles. However, within each pair the clear separation between SAP and CRP was invariable except in Tris/phosphate or in the presence of MOβDG and calcium. SAP, serum amyloid P component; CRP, C-reactive protein; FPLC, fast [protein] liquid chromatography; MOβDG, methyl-4,6-O-1-carboxyethylidine-β-D-galacto-pyranoside; TN Buffer, TE buffer,.

ISSN: 1528-3658