This is a good article on pruning and it addresses your question as well:

http://www.taunton.com/finegardening/how-to/articles/pruning-tomatoes.aspx

If you prune or remove the suckers from determinate plants you may not get hardly any fruit, as they depend on these to fruit on usually, and differ from indeterminates in this way and must be treated differently.

They are usually of bush type and used mainly for field growing/or garden short plants too.

Sorry Christopher but yes, those aren't "suckers" when on determinates. They are the fruiting branches. Please leave the remainder of them and you'll still get fruit.

Are these purchased plants? If so, they should have been marked as det. vs. indet. Unfortunately, some growers just assume that everyone knows which are which and that is far from the truth.

Dave