Table 2. Kinetic parameters (k_unw^max and K_1/2) of TRAMP^WT and TRAMP^R1030A for unwinding poly(A) and non(A) substrates^a.

	poly(A)	non(A)	poly(A)	non(A)
Enzyme	kunwmax (min−1)	kunwmax (min−1)	K (nM)	K (nM)
TRAMPWT	1.96 ± 0.75	0.57 ± 0.41	497 ± 268	238 ± 300
TRAMPR1030A	0.42 ± 0.06	0.52 ± 0.08	24 ± 19	32 ± 23

Data presented here represent averages from at least three independent experiments; error bars represent SD. The non-catalytically functional Trf4(D236/D238A) mutant was used for all TRAMP preps.

^aMethodologies and equations used to derive kinetic constants are found in the ‘Materials and Methods’ section.