Enzymes such as associated with phage infections or virions that degrade extracellular polymers produced by bacteria.
EPS depolymerases act particularly against the extracellular polymeric substances (EPS) of bacteria that serve as hosts by the so-producing phages, e.g., such as can make up biofilms. These enzymes tend to display high levels of specificity and bacteria too can display high levels of EPS diversity, potentially to at least some degree in response to phage expression and display of these enzymes.
As noted, EPS depolymerases can be found in direct associated with phage particles or instead can be soluble enzymes. Often if the former is true then the latter will be true as well (though not necessarily vice versa, i.e., either virion associated and soluble or just soluble). Association with virions allows for EPS depolymerase utility during the adsorption process, that is, as moving towards bacteria, whereas soluble enzymes are useful particularly in the moving away from bacteria process. The two processes though can be more or less equivalent if bacteria are sufficiently closely associated such as into microcolonies.
Note that EPS depolymerases can aid in phage movement towards or away from target bacteria. They also can be employed as potential biofilm-dispersing agents. In addition, the production of EPS depolymerases can result in the formation of halos during plaque formation, that is, plaque halos.
EPS depolymerases have been reviewed in a number of places. For emphasis on their role in phage ecology and therapy, see Abedon (2011).
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