sugars Flashcards
what is the structure of heparin
oligosaccharide
what is heparin?
anticoagulant
give examples of monomers
glucose
fructose
galactose
mannose
how can you modify sugars?
replace the OH group with an amine, phosphate or sulphate
remove the OH group
give an example of a sugar phosphate and how its made
glucose 6-phosphate
phosphorylation of glucose using ATP
name some sulphated sugars
chondroitin sulfate
heparan sulfate
dermatan sulfate
what enzyme makes sulphated sugars?
sulpho-transferase
what is the role of sulphated sugars?
ECM - negative so they can hold water
lubricants and shock absorbers
what catalyses the formation of a glycosidic bond?
glycosyl transferase
what enzymes are used to break glycosidic bonds?
hydrolases
describe the structure of glycogen
alpha glucose
main chain is a-1,4
side chains are a-1,6
what is the role of glycogen
energy store in liver and muscles
broken down by glycogen phosphorylase
name disaccharides and what they’re made up of?
- Maltose (Glc-Glc)
- Sucrose (Glc-Fru)
- Lactose (Gal-Glc)
what bond is in disaccharides?
glycosidic bond
what are oligosaccharides?
3-10 monosaccharides
what are blood group antigens?
oligosaccharides
what are enantiomers?
Pair of isomers that are (non-superimposable) mirror images
what is the D and L form of enantiomers?
- D-form: OH group attached to the right of the asymmetric carbon
- L-form: OH groups attached to the left of the asymmetric carbon
can D glucose be digested?
yes
what is L glucose used for?
laxative
used in no calorie foods
what are the 2 stereoisomers of glucose and which is more stable?
alpha and beta
beta is more stable
how does glucose form a ring structure?
OH on C5 reacts with the aldehyde/ketone group
how can sugars be modified?
OH group replaced with • Amine (NH2) = amino sugars • Sulphate (SO4) = sulphated sugars • Phosphate (PO4) = phosphorylated sugars • Removal of OH = deoxy sugar
what enzyme makes sulphated sugars?
sulpho-transferase
how are sugar sulfates used?
as GAGs in the ECM e.g.
chondroitin sulphate
Heparan sulphate
Dermatan sulphate
also as lubricant or shock absorber
give structure to connective tissue
what type of reaction is the formation of a glycosidic bond?
dehydration/condensation
what catalyses the formation of glycosidic bonds?
glycosyl transferase
what will the glycosyl enzyme differ according to?
D or L form
alpha or beta anomer
location of OH group
type of bond
what is the breakdown of a glycosidic bond?
hydrolysis
what enzymes carry out hydrolysis?
hydrolases
what is glycogen?
polymer of glucose
describe the structure of glycogen?
main chain has glycosidic bonds - alpha 1,4
side chains have beta 1,6 chains
describe the structure of amylose?
straight chain with alpha 1,4 links
what is the subunit of glycogen?
alpha glucose
what is the subunit of cellulose?
beta glucose
what is the subunit of starch?
alpha glucose
does cellulose have branches?
no
