Table 1.

Control substrates and reaction buffers used in the activity assay of BER enzymes

Substrate	Damage (X)a	Sequenceb	Enzyme testedc
19U	U	ACAGACGCCAXCAACCAGG	Ung, hSMUG1
		TGTCTGCGGTGGTTGGTCC
34MG	7mG	GAAACACTACTXTCACCCTCCATACCCACATCCT	AlkA, hMPG
		CTTTGTGATGACAGTGGGAGGTATGGGTGTAGGA
25HX	Hx	GAAACACTATTCCACXCCTTCTCTC	HeLa CFE1s, hMPG
		CTTTGTGATAAGGTGTGGAAGAGAG
19TG	Tg	ACAGACGCCAXCAACCAGG	Endo III, Endo VIII
		TGTCTGCGGTAGTTGGTCC	hNTH1, hNEIL1
25OG	8oxoG	CATCGATAGCATCCTXCCTTCTCTC	Fpg, hOGG1
		GTAGCTATCGTAGGACGGAAGAGAG
19AP	AP	ACAGACGCCAXCAACCAGG	Endo IV, hNEIL2
		TGTCTGCGGTGGTTGGTCC

^aU, uracil; 7mG, 7-methylguanine; Hx, hypoxanthine: Tg, thymine glycol; 8oxoG, 7,8-dihydro-8-oxoguanine; AP, abasic site.

^bTop strands containing damage were 5′-end ³²P-labeled.

^cReaction buffer used: 20 mM Tris–HCl (pH 8.0), 1 mM EDTA and 1 mM DTT (Ung); 25 mM Tris–HCl (pH 7.5), 50 mM NaCl, 0.2 mM EDTA and 2 mM DTT (hSMUG1); 50 mM HEPES–KOH (pH 7.5), 1 mM EDTA and 5 mM 2-mercaptoethanol (AlkA); 50 mM HEPES–KOH (pH 7.5), 100 mM NaCl, 1 mM EDTA, 5 mM 2-mercaptoethanol (hMPG and HeLa CFE1s); 10 mM Tris–HCl (pH 7.4), 100 mM NaCl and 1 mM EDTA (Endo III, Endo VIII, Fpg and hNEIL1); 10 mM Tris–HCl (pH 7.5), 50 mM NaCl and 1 mM EDTA (Endo IV and hNEIL2); and 50 mM Tris–HCl (pH 7.5), 50 mM NaCl, 1 mM EDTA and 1 mM DTT (hOGG1 and hNTH1).