The dalton, symbol Da, is also sometimes used as a unit of molar mass, especially in biochemistry, with the definition 1 Da = 1 g/mol, despite the fact that it is strictly a unit of mass (1 Da = 1 u = 1.660 538 921(73)×10−27 kg).
So I reckon 66kDa = 66000 g/mol
Looking at this article https://en.wikipedia.org/wiki/Hsp70 This link gives a list of proteins in the HSP70 family
Further info about HSP - https://en.wikipedia.org/wiki/Heat_shock_protein
For more details, please check the link: