Table I.

Molecular weights of native ONC and its AEMTS-blocked intermediates, I₁, I₂ and I₃

Observed chromatographic peaks of Fig. 1	Experimental MW of ONC species in Fig. 1, blocked with AEMTSa	Theoretical MW of ONC species blocked with AEMTS	Number of disulfide bonds in each species in Fig. 1
N	11 820b	11 819b,c	4
I3	11 970	11 971	3
I2	11 971	11 971	3
I1	12 121	12 123	2
R	12 427	12 427	0

Each AEMTS adduct adds 76 Da to the molecular weight of the native protein.

^aMass measurements were made on a MALDI-TOF MS instrument.

^bN cannot be blocked with AEMTS.

^cArdelt et al. (1991).