You need 2500TT and 1000 Part 121 time. You will probably enjoy a pretty nice schedule until you have the time to upgrade.
I think it's 1000 crew/turbine, not only 121 time. I've even heard of people getting some credit for turbine 135 time, like flying the BE-99 for amflight or something. 2500TT is non-negotiable.
Scott