Table I. Relative affinities^a of Nak peptides for the dNumb PTB domain.

Peptide	Sequence	Rel. affinity (%)
	–6–4–20+2+4
Nak–c	G-F-S-N-M-S-F-E-D-F-P	100
G-6A	A-F-S-N-M-S-F-E-D-F-P	135
F-5A	G-A-S-N-M-S-F-E-D-F-P	66
S-4A	G-F-A-N-M-S-F-E-D-F-P	250
N–3A	G-F-S-A-M-S-F-E-D-F-P	N/D
M-2A	G-F-S-N-A-S-F-E-D-F-P	400
S-1A	G-F-S-N-M-A-F-E-D-F-P	851
F0A	G-F-S-N-M-S-A-E-D-F-P	3.5
E+1A	G-F-S-N-M-S-F-A-D-F-P	82
D+2A	G-F-S-N-M-S-F-E-A-F-P	27
F+3A	G-F-S-N-M-S-F-E-D-A-P	92
Nak-AA	G-F-S-N-A-A-F-E-D-F-P	1500
NakΔC	G-F-S-N-M-S-F-E	<1
Nak▿N	S-A-K-T-G-F-S-N-M-S-F-E-D-F-P	95
N–TrkA/	H-I-I-E-N-M-S-F-E-D-F-P	<1
C–Nak

^aRelative affinities were calculated according to the IC₅₀ (concentration for 50% inhibition of binding) value of an individual peptide when competing against fluorescein-labeled peptide Nak–c for binding to the dNumb PTB domain. Relative affinities were normalized to that of the unlabeled Nak–c peptide, set to 100%. Repetition of the measurements produced values with <5% deviation from those reported.