Evaluation of Molecular Species of Prostate-Specific Antigen Complexed with Immunoglobulin M in Prostate Cancer and Benign Prostatic Hyperplasia

Table 2

Assessment of glycosylation of PSA molecular species complexed with IgM.

PSA amino acid sequence theoretical mass^1	PSA group^2	PSA		PSA glycan (G)		Glycan (G)
		Observed mass		Calculated mass^3		Theoretical mass	Putative composition^4	Structure
		PCa	BPH	PCa	BPH
1–145 (16123.50) + G	gp18	17136.81	17126.76	1013.31	1003.26	1054.96	Man4
		17254.85	17244.57	1131.35	1121.07
		17382.81	17377.32	1259.31	1253.82	1217.11	Man5
1–237 (26089.11) + G	gp28	26889.27		800.16		730.69
						892.82	MM
		28070.48	28049.52	1981.37	1960.41	1899.00	GnNaF/NaGnF
						1933.70	NaA/ANa
		28237.86	28241.03	2148.75	2151.92	2061.00	ANaF/NaAF
						2120.80	NaGnFbi/GnNaFbi
		28908.06	28906.73	2818.95	2817.62	2862.60	Na[NaNa]/[NaNa]Na

1Theoretical average masses of PSA amino acid sequences were obtained using PeptideMass software (http://web.expasy.org/peptide_mass/peptide-
mass-doc.html).
²According to Isono et al., 2002 [8].
³PSA glycan mass was calculated as the difference between observed PSA mass and theoretical mass of corresponding PSA protein sequence.
⁴Putative glycan compositions were proposed based on established complete PSA glycan chain (NaNaF, 2352.16 Da). It is depicted using the nomenclature of the Consortium for Functional Glycomics.
+G: glycosylation.
The blue square: Gn (N-acetylglucosamine); the green circle: M or Man (mannose); the yellow circle: A (galactose); the red triangle: F (fucose); the purple diamond: Na (sialic acid); bi: (bisected).