Арабиноза-L

Описание

L-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.

Химические свойства

L-Arabinose is a white crystalline powder, It is a rare type of C5-sugar that naturally occurs in the hemicelluloses structure of most fruits and vegetables. Its name is derived from gum Arabic, another well-known food ingredient. Humans have always consumed L-Arabinose both pure as well as part of the hemicelluloses structure. The highest concentrations of L-Arabinose in food as monosaccharide can be found in instant coffee, wine and sake.

Вхождение

For 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.

Использование

The 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.

Подготовка

By partial hydrolysis of mesquite gum.

Определение

l-enantiomers occur naturally. lArabinose is common in vegetable gums, especially arabic.

прикладной

L-Arabinose is used as a substrate to identify, differentiate and characterize pentose sugar isomerase(s). L-Arabinose is used in the bioproduction of L-ribose.
L-(+)-Arabinose is a pentose sugar that occurs naturally in corn fiber gum and acacia gum.
L-(+)-Arabinose is used as a key starting material in the total synthesis of (+)-ambruticin, zaragozic acid A, (?)-radicamine B and (+)-herbarumin I.

преимущество

L-Arabinose can play an important role in the management of blood glucose and insulin levels related to sucrose intake. The addition of L-Arabinose to a sugar containing diet has the following direct benefits: 1) up to 60% reduction of the glucose peak level related to sucrose consumption, 2) up to 60% suppression of the insulin peak level related to sucrose consumption, and 3) a sustained release of glucose to the body over a longer period of time. A low glycemic diet may have benefits like reduction of heart disease, lowering of blood cholesterol, management of body weight and composition, and prevention of type 2 diabetes. A low insulinic diet may lead to lower fat storage and prevention of pre-diabetes incidence. Sustained glucose release over a longer period of time has advantages for athletes and other people that value a responsible and healthy diet.

Биологическая активность

L-Arabinose is the naturally occurring isomer and is a constituent of plant polysaccharides. Most bacteria contain an inducible arabinose operon that codes for a series of enzymes and transporters that allows L-arabinose to be used as the sole carbon source in microbial culture.