Molecular gas and star formation in galaxy interactions

Galaxy interaction can affect strongly the star formation activity and the molecular gas content of galaxies. Frequently, interaction enhances both quantities, but this is not always the case. I will present results for the effect of interaction on the molecular gas and star formation in different environments, in compact groups and in close major mergers pairs. In both cases, there are subsamples of galaxies that show no enhancement, or even a suppression  of  the star formation rate and the molecular gas content. Possible reasons for this behaviour will be discussed.