Target type: molecularfunction
Binding to lactose, a disaccharide of glucose and galactose, the carbohydrate of milk. [GOC:jl, ISBN:0192800981]
Lactose binding is a molecular function that involves the specific recognition and interaction of a protein or other molecule with lactose, a disaccharide composed of glucose and galactose. This binding process typically occurs through non-covalent interactions, such as hydrogen bonding, van der Waals forces, and hydrophobic interactions. The specific amino acid residues involved in the binding site determine the affinity and specificity of the interaction. Lactose binding is essential for various biological processes, including:
**1. Lactose Transport and Metabolism:** Lactose binding proteins, such as lactose permease (LacY) in bacteria, facilitate the uptake of lactose into cells. This process is crucial for the utilization of lactose as an energy source.
**2. Lactose Sensing and Regulation:** Lactose binding proteins can act as sensors for lactose availability. For example, in the lac operon of bacteria, the lactose repressor protein (LacI) binds to the operator region of the operon and prevents transcription of lactose-metabolizing genes. However, when lactose is present, it binds to LacI, causing a conformational change that releases LacI from the operator, allowing gene expression.
**3. Immune System Function:** Lactose binding is involved in the recognition of lactose by immune cells, such as macrophages and dendritic cells. This interaction can trigger immune responses and influence the immune system's ability to recognize and eliminate pathogens.
**4. Food Industry Applications:** Lactose binding proteins are used in the food industry for applications such as cheese production and lactose-free milk production.
In summary, lactose binding is a complex molecular function that plays a significant role in various biological processes, including transport, metabolism, sensing, and immunity. The specific details of the binding process and its biological consequences can vary depending on the protein involved and its cellular context.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Beta-galactoside-binding lectin | A protein that is a translation product of the LGALS1 gene in chicken. [PRO:DNx, UniProtKB:P07583] | Gallus gallus (chicken) |
| Galectin-1 | A galectin-1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P09382] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| lactose | beta-lactose : The beta-anomer of lactose. lactose : A glycosylglucose disaccharide, found most notably in milk, that consists of D-galactose and D-glucose fragments bonded through a beta-1->4 glycosidic linkage. The glucose fragment can be in either the alpha- or beta-pyranose form, whereas the galactose fragment can only have the beta-pyranose form. Lactose: A disaccharide of GLUCOSE and GALACTOSE in human and cow milk. It is used in pharmacy for tablets, in medicine as a nutrient, and in industry. | lactose | |
| methyl alpha-d-galactopyranoside | methyl alpha-D-galactoside : An alpha-D-galactoside having a methyl substituent at the anomeric position. methyl-galactopyranoside: structure in first source | alpha-D-galactoside; methyl D-galactoside; monosaccharide derivative | |
| methyl beta-galactoside | methyl beta-D-galactoside : A beta-D-galactopyranoside having a methyl substituent at the anomeric position. methyl beta-galactoside: RN given refers to (beta-D)-isomer methyl galactoside : A methyl glycoside in which the H of the OH group on C-1 of galactose is replaced by a methyl group. | beta-D-galactoside; methyl D-galactoside; monosaccharide derivative | |
| thiodigalactoside | thiodigalactoside: RN given refers to beta-D-galactopyranoside (D-Gal)-isomer | ||
| methyl lactoside | beta-D-Gal-(1->4)-beta-D-Glc-OMe : A methyl glycoside comprising methyl beta-D-glucoside having an beta-D-galactosyl residue at the 4-position. | disaccharide derivative; methyl glycoside | |
| n-acetyllactosamine | N-acetyllactosamine : A beta-D-galactopyranosyl-(1->4)-N-acetyl-D-glucosamine having beta-configuration at the reducing end anomeric centre. N-acetyllactosamine: RN given refers to D-isomer | beta-D-Galp-(1->4)-D-GlcpNAc | |
| galactose | alpha-D-galactoside : Any D-galactoside having alpha-configuration at its anomeric centre. | D-galactopyranose | mouse metabolite |
| galactal | galactal: RN given refers to cpd with unspecified isomeric designation; structure | anhydrohexose; glycal | |
| allolactose | glycosylglucose | Escherichia coli metabolite | |
| pf-2545920 |