L-Arabinose

BeschreibungL-Arabinose is considered a rare sugar that can be found naturally within the structures of most fruits and vegetables. Due to its low caloric sweetening effects, arabinose is commonly used in nutritional supplements and prescription drugs. In addition to its sweetening effects, when reacted with amino acid blends, using the Maillard Reaction, arabinose is able to contribute to the production of savory and meaty flavors used within the food and flavor industry.L-Arabinose is commonly used in the Flavor Industry to produce meaty or cooked/roasted flavors.

OccurrenceFor biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde. However, L-arabinose is in fact more common than D-arabinose in nature and is found in nature as a component of biopolymers such as hemicellulose and pectin. L-Arabinose is widely distributed in nature including Acacia and Larix species as a complex polysaccharide.

VerwendenThe L-arabinose operon, also known as the araBAD operon, has been the subject of much biomolecular research. The operon directs the catabolism of arabinose in E. coli, and it is dynamically activated in the presence of arabinose and the absence of glucose. In synthetic biology, arabinose is often used as a one-way or reversible switch for protein expression under the Pbad promoter in E. coli. This on-switch can be negated by the presence of glucose or reversed off by the addition of glucose in the culture medium which is a form of catabolite repression. L-Arabinose is an arabinose isomer widely found in nature, while D-arabinose is less common. L-Arabinose is a constituent of many biopolymers that make up plant cell walls. This monosaccharide is often used in cell culture media, serving as a bacterial carbon source, and can be used to distinguish between bacteria based on their fermentation abilities. L-Arabinose, in the absence of glucose, induces transcription of the ara operon in E. coli that encodes L-arabinose catabolizing enzymes. It does this by binding to the AraC protein and activating the PBAD promoter. The PBAD promoter is used in plasmid vectors as a switch for protein expression that can be turned on by L-arabinose or turned off by addition of glucose.