melibiose

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 304512290

| ImageFile=Melibiose structure.svg

| ImageSize=200px

| IUPACName=6-O-α-D-Galactopyranosyl-β-D-glucopyranose

|SystematicName=(2R,3R,4S,5S,6R)-6-[[(2S,3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxymethyl]oxane-2,3,4,5-tetrol

| OtherNames=

|Section1={{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 585-99-9

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 9B1VBE526I

| PubChem=11458

| ChEBI_Ref = {{ebicite|changed|EBI}}

| ChEBI = 28053

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| ChEMBL = 1159652

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 10974

| InChI = 1S/C12H22O11/c13-1-3-5(14)8(17)10(19)12(23-3)21-2-4-6(15)7(16)9(18)11(20)22-4/h3-20H,1-2H2/t3-,4-,5+,6-,7+,8+,9-,10-,11-,12+/m1/s1

| InChIKey = DLRVVLDZNNYCBX-ZZFZYMBESA-N

| SMILES=C([C@@H]1[C@@H]([C@@H]([C@H]([C@H](O1)OC[C@@H]2[C@H]([C@@H]([C@H]([C@@H](O2)O)O)O)O)O)O)O)O

| MeSHName=Melibiose

}}

|Section2={{Chembox Properties

| C=12 | H=22 | O=11

| Appearance=

| Density=

| MeltingPtC=84-85

| BoilingPt=

| Solubility=

}}

|Section3={{Chembox Hazards

| MainHazards=

| FlashPt=

| AutoignitionPt =

}}

}}

Melibiose is a reducing disaccharide formed by an α-1,6 linkage between galactose and glucose (D-Gal-(α1→6)-D-Glc).{{cite book |title=Essentials of Carbohydrate Chemistry and Biochemistry |author=Thisbe K. Lindhorst |authorlink=Thisbe Lindhorst|publisher=Wiley-VCH |edition=1 |year=2007 |isbn=978-3527315284}}{{cite book |title=Essentials of Carbohydrate Chemistry |publisher=Springer |author=John F. Robyt |edition=1 |year=1997 |isbn=0387949518}} It differs from lactose in the chirality of the carbon where the galactose ring is closed and that the galactose is linked to a different point on the glucose moiety. It can be formed by invertase-mediated hydrolysis of raffinose, which produces melibiose and fructose. Melibiose can be broken down into its component saccharides, glucose and galactose, by the enzyme alpha-galactosidase, such as MEL1 from Saccharomyces pastorianus (lager yeast).

Melibiose cannot be used by Saccharomyces cerevisiae{{cite web | url=http://mmbr.asm.org/content/77/2/157.full | title=The Microbiology of Malting and Brewing | publisher=American Society for Microbiology | date=1 June 2013 | accessdate=2 May 2015 | author=Bokulicha. Nicholas A. & Bamforth. Charles W. | pages=157–172}} (ale yeast), so this is one test to differentiate between the two yeast species.