Table 1.

Molecular masses of recombinant TSPs and α₂δ-1_S NTST obtained by MALDI-TOF MS.

Protein	m/zcalc [M + H]+	m/zexp [M + H]+
TSP-2 (monomer)	132,137	146,958
TSP-4 (monomer)	107,409	109,351
COMP (monomer)	84,714	88,463; 87,178
α2δ-1S NTST (−DTT)	123,000	152,236
α2δ-1S NTST (+DTT)	112,130*	152,258

The m/z_calc [M + H]⁺ values for all proteins (in Da) were calculated based on their amino acid sequences using ExPASy Compute pI/Mw online tool, while the m/z_exp [M + H]⁺ values (in Da) were obtained from the MALDI-TOF MS spectra of the respective proteins.

^* m/z_calc [M + H]⁺ of α₂ NTST was calculated for the expected product of the DTT-mediated reduction of the disulphide bond between α₂ and δ-1_S in α₂δ-1_S NTST.