1. A shut-off valve (1) for a pressurized-gas vessel, the shut-off valve (1) comprising a valve closing body (2) which is configured to perform stroke movements and which is preloaded against a valve seat (4) by a spring force of a closing spring (3), with a result that, when the valve closing body (2) is in a closed position, a connection of a valve inlet (5) to a valve outlet (6) is shut off, and furthermore comprising an actuator arrangement (7) for opening the valve closing body (2), wherein the actuator arrangement (7) interacts with an actuating element (8) which is arranged at a distance from and coaxially with the valve closing body (2) and which is configured to be moved in a direction of the valve closing body (2) by the actuator arrangement (7), such that, when the actuating element (8) strikes the valve closing body (2), an opening momentum is generated, wherein an opening stroke of the valve closing body (2) is limited by a stop (13), and an electromagnet (14) for holding the valve closing body (2) in an open position is arranged in a region of the stop (13), wherein the valve closing body (2) achieves a maximum opening cross section of the shut-off valve (1) when the actuating element (8) has returned to an initial position after energization of the actuator element (8).