Rhamnose (Rham) is a naturally occurring
deoxy sugar. It can be classified as either a methyl-
pentose or a 6-deoxy-
hexose. Rhamnose occurs in nature in its
L-form as
L-rhamnose (6-deoxy-
L-
mannose). This is unusual, since most of the naturally occurring sugars are in
D-form. Exceptions are the methyl pentoses
L-
fucose and
L-rhamnose and the pentose
L-
arabinose.