Table 1. Michaelis constants of O-GlcNAc-modified peptides for hOGA.

K_m values for peptides derived from the O-GlcNAc sites of two known substrate proteins were determined in a competitive assay with the fluorigenic substrate 4MU-GlcNAc. Ac, acetyl; amino acids in peptides are indicated using the single-letter code.

Substrate	Km
hOGA-Ser405-derived peptide series
Ac-HS(-β-O-GlcNAc)G-NH2	525±13 μM
Ac-VAHS(-β-O-GlcNAc)GA-NH2	1204±43 μM
Ac-VAHS(-β-O-GlcNAc)GAK-NH2	789±36 μM
Ac-QVAHS(-β-O-GlcNAc)GAKAS-NH2	528±15 μM
TAB1-Ser395-derived peptide series:
Ac-YS(-β-O-GlcNAc)S-NH2	2.2±0.1 mM
Ac-PYS(-β-O-GlcNAc)SA-NH2	6.3±0.5 mM
Ac-VPYS(-β-O-GlcNAc)SAQ-NH2	4.1±0.3 mM
Ac-SVPYS(-β-O-GlcNAc)SAQS-NH2	4.8±0.3 mM