Table 1.

Selected features of human DNA polymerases [4, 7, 40–42, 64, 67, 83, 84, 95, 114, 121, 135, 136, 259, 282, 288]

Family	Pol	Catalytic subunit mass(kDa)	Structure without DNAa	DNA bound structurea	Fidelityb	Additional subunits	Biological pathwayc
B	Alpha (α)	165	4B08	4Q5V, 5IUD	10−4	Subunit B, primase large, and primase small subunit	DNA replication
	Delta (δ)	100		3IAY	10−5	PolD2, PolD3, and PolD4	DNA replication
	Epsilon (ε)	225		4M8O, 4PTF	10−5	p59, p12, and p17	DNA replication
	Zeta (ζ)	353	3ABD		10−3 f	Rev7, PolD2, and PolD3	TLS
Y	Eta (η)	78		3MFH	10−2	Monomer	TLS
	Iota (ι)	80		1T3N, 2FLN, 4EYH	10−1	Monomer	TLS
	Kappa (κ)	76	1T94	2OH2, 4U6P, 6CST	10−3	Monomer	TLS
	REV1	138		2AQ4, 5WM8, 3BJY	N.A.d	Monomer	TLS
X	Beta (β)	39	1BPB, 1RPL	2BPG, 2FMS, 31SB	10−4	Monomer	BER
	Lambda (λ)	66	5CB1	1RZT, 2BCQ	10−3	Monomer	BER, NHEJ, TLS
	Mu (μ)	55	4LZD	2IHM, 4LZG	10−3	Monomer	NHEJ, V(D)J
	TdT	56	1JMS	4I27	N.D.e	Monomer	V(D)J recombination
A	Gamma (γ)	140	3IKM	4ZTZ, 5C53	10−5	Two copies of subunit 2	Mitochondrial DNA replication and repair
	Theta (θ)	290		4X0P	10−3	Monomer	TLS, MMEJ
	Nu (v)	100		4XVK	10−3	Monomer	ICL repair

^aRepresentative crystal structures discussed in this review

^bApproximate error rate for single-base substitutions

^cThis column focuses on the primary biological pathway(s) of each polymerase; others may also apply

^dFidelity measurements are not applicable to REV1

^eNo data could be found for the fidelity of TdT’s templated activity, although it is likely similar to other X family polymerases

^fMeasurement from yeast homolog