Table 7.

Calf thymus/bovine DNA helicases.

S. No.	Name of helicase	Mol. mass (kDa)	Nucleotide cofactors	Polarity	Remarks
1.	DNA helicase A a	47	ATP = dATP > CTP > dCTP	3′−5′	Copurifies with calf thymus DNA Pol‐α/?Primase; stimulated 20‐fold by RPA.
2.	DNA helicase B b	100	dATP = ATP ≫ all other	5′−3′	Binds to dsDNA also.
3.	DNA helicase C c	40	dATP = ATP ≫ all other	5′−3′	Stimulated by 100 mm KCl on short substrates.
4.	DNA helicase D d	100 45	dATP = ATP	5′−3′	Stimulated 10‐fold by RPA and forms large aggregates in low salt.
5.	DNA helicase E e	104	dATP = ATP	3′−5′	Copurifies with DNA Pol‐ε and dependent on unspecific SSB; probably involved in DNA repair.
6.	DNA helicase F f	72	ATP, dATP, dCTP, UTP, CTP, GTP, dGTP, dTTP	5′−3′	Copurifies with RPA. In presence of RPA, this helicase can unwind longer duplexes
7.	DNA helicase I g	200	ATP = dATP	3′−5′	Stimulated by 150 mm NaCl.
8.	DNA helicase II h	130	ATP = dATP ≫ 1 other	3′−5′	Can unwind dsRNA also.
9.	δ helicase i	57	ATP = dATP > CTP = UTP	5′−3′	Copurifies with DNA Pol. δ and acts as strand‐ displacement factor for Pol.δ
10.	Cytosolic DNA helicase j	110	ATP = dATP > CTP, dCTP	3′−5′	All the three subunits bind to ATP.
		65
		34
11.	Bovine mitochondrial helicase k	57	ATP = dATP	3′−5′	Possible role in mitochondrial DNA replication.

^a [ 108]; ^b [108]; ^c [108]; ^d [108]; ^e [109]; ^f [110]; ^g [111]; ^h [111]; ⁱ [100]; ^j [112]; ^k [64].