Anomer

In carbohydrate chemistry, an anomer is a specific type of stereoisomer known as an epimer that differs in configuration at the anomeric carbon atom. The anomeric carbon is the carbon that was the carbonyl carbon (aldehyde or ketone) in the open-chain form of the sugar. When a sugar cyclizes to form a ring, the carbonyl carbon becomes a chiral center, and the two possible configurations at this carbon lead to two different anomers.