As you are connecting to a domestic flight you will need to pass through immigration. At Istanbul airport, this can take anywhere between a few minutes and 30+ minutes depending on the time of day and how busy they are at the time.
As the airport you are connecting to does not have Customs, you will need to collect your bags at Istanbul and take them through customs there. If the airport you were connecting to did have customs then you could avoid this step.
Next you will need to proceed to the domestic terminal (a 10-15 minute walk from the International Arrivals area) where you will be able to re-check your luggage, go through security, and board your domestic flight.
100 minutes for all of this is possible - but tight. If you need a visa to enter Turkey make sure that you have arranged this in advance (to save having to line up at the visa-on-arrival counter first), and once you land don't waste any time!