I don't wish to jump the queue and answer in Nathu's place (or Nanda), but there are a few things you can use to tenderise meat. It is a bit difficult if you do not know what it is called in English ...

The most commonly used ingredient is bi-carbonate of soda, which is called "Natron" or "Back-Natron" in German. You can find this in the baking section of your supermarket, and they are often sold in small sachets.

Though, foodies at heart would not use bi-carb to tenderise meat. It often turns the meat into a very soft, chewy texture which does not resemble anything close to what its normal state should be. Plus, the bi-carb also alters the taste of the meat. I am always bitterly disappointed when I go to a restaurant (especially Chinese restaurants) and find myself served with cheap meat that has been sitting in bi-carb and pretending to be fillet steak.

You should instead buy good quality meat to start with