Amylase Enzyme is typically used by all-grain brewers to add to a high adjunct mash that may be low in enzymes to aid in converting starches into sugar. You can also use it to unstick a fermentation, provided the issue was in your starch conversion in your mash. This enzyme can also prevent starch haze in beer. Use 1 teaspoon per 5 gallon batch.
More technical information:
Breaks 1,4 linkage in starch during liquefication, producing dextrin and a small amount of maltose. Leaves 1,6 links, therefore self-limiting.