Table I.

Peptides corresponding to three FLAs obtained from a trypsin digest of hydrophobic fraction four of β-glucosyl Yariv precipitated proteoglycans (see Fig. 3)

Protein	Peptide Sequencea	Trypsin Fractionb	Position in Protein	Predictedc	Mass Observedd	Difference
FLA7	(F)VPKDDAFK	T3	88-95	919.489	919.47	0.019
FLA7	(K)FTDVSGTVRe	T2	149-157	981.501	981.558	−0.057
FLA7	(K)NPPLSNLTKe	T2	99-107	983.557	983.569	−0.012
FLA7	(F)STDPVAVYQVNRe	T5	167-184	1,348.686	1,348.732	−0.046
FLA2	(K)TALVLY	T9	250-255	679.403	679.421	−0.018
FLA2	(K)FMPKFK	T4, T5	237-242	797.438	797.435	0.003
FLA2	(F)QSTGSATGTSGY	T1	117-128	1,099.454	1,099.496	−0.042
FLA2	(Y)SLYQIRNILSLHVLVDYF	T11	80-97	2,193.207	2,193.259	−0.052
FLA8	(K)LADEINSR	T3	50-57	917.47	917.486	−0.016
FLA8	(Y)HALAEYKPK	T1	256-262	1,056.584	1,056.51	0.074
FLA8	(K)TFANLLVSSGVLK	T5	201-213	1,348.784	1,348.717	0.067
ENOD likef	(K)LSLVVISPR	T2	121-129	983.625	983.668	−0.043

^a Theoretical digest of FLA protein backbone with “msdigest” (http://prospector.ucsf.edu) was performed. Peptides shown had close agreement between predicted (c) and observed (d) masses. The first amino acid is predicted (parentheses) because it is the residue important for defining the trypsin cleavage site, but is not observed in the peptide. ^b Trypsin-digested fraction four of hydrophobic AGPs (see Fig. 3) was separated by RP-HPLC into 11 fractions (see Fig. 4A). ^c Predicted molecular mass of the FLA peptides. ^d Observed molecular mass inferred by MALDI-TOF MS of a trypsin-digested fraction of hydrophobic AGPs (see Fig. 4). ^e Peptide sequence was also determined using Edman degradation chemistry. ^f Early nodulin-like protein from Arabidopsis (GenBank accession no. AAD23007). Another peptide (residues 77-96) for this ENOD-like protein was sequenced by N-terminal sequencing (Table II).