Glycoprotein + Polysacc + Disacc

Reducing sugar:

monosaccharides and disaccharides with a free,

reactive carbonyl group or anomeric carbon

Non-reducing sugar:

disaccharides with both

anomeric carbons involved in

glycosidic bond formation

• Fructose is an example

When naming disacharides

The non-reducing sugar is labeled first, on the left

• Important to give the alpha or beta and D and then name of sugar and type of ring and then type of linkage between the sugars

What is the glycosidic bond

primary structural linkage of all monosaccharide polymers

A ring with an unreacted anomeric carbon is still in equilibrium with the

open form and can be _____

oxidized

T/F: The anomeric carbon, even in hemiacetal

(or hemiketal) state is reactive, and there are

a number of compounds that contain sugars

joined through a glycosidic bond –

nucleosides, bonds between

oligosaccharides and lipids or proteins;

these reactions displace the hydroxyl

true

What is amylose and amylopectin (starches) used for?

energy storage

What is glycogen in animals used for

energy storage

What are structural polysaccharides?

Chitin and cellulose

What are the linkages of Amylose

Amylose is a homopolysaccharide of glucose that is made for energy storage. It is a linear polymer linked by alpha 1→ 4 D-glucosidic bonds

What is amylopectin’s linkages:

alpha 1→ 6 D-glucosidic bonds

Glycogen has the same structure as amylopectin, but more frequent 1→ 6 branches and shorter linear regions.

What does amylopectin look like

is it branched!

What does glycogen look like?

It is made up of only glucose in alpha 1 → 4 linkages and Beta 1 → 6 linkages (branch linkages).

• it is highly branched

What bonds does cellulose have?

Beta 1 → 4 linkages

b-D-Glucopyranosyl-(1 → 4)-b-D-glucopyranose

• The strength of cellulose comes from packing of cellulose and by H-bonding stabilization between polymers

Animals are not able to break these beta 1→4 linkages, which is why we cannot digest cellulose. We lack the Beta glycosidase enzyme

What is a homoglycan of N-acetylglucosamine?

chitin

It is structurally similar to cellulose: glycosidic bonds are exclusively b-(1 → 4);

The structure is linear, straight and extended if alternating sugars are rotated

What is this?

cellulose

What is this?

Chitin

What are glycoproteins?

have one or more oligosaccharides of varying complexity joined covalently to a membrane protein or secreted protein; the oligosaccharide part of the molecule usually ends up extracellular. It also contains a glycophosphatidylinositol membrane anchor. and a protein ribbon.

What can be O-linked?

Through the O atom of the side chain

hydroxyl of Ser, Thr, Hydroxy-lysine (Hyl)

Commonly linked to N-Acetylgalactosamine (think O-gal)

What is N-linked?

Through the N

atom of the side chain

carboxylamine of Asn (NOT Gln) —> N-Acetylglucosamine

What are N-linked glycans used for?

USED for recognition:

example: antibodies are glycosylated to interact with

phagocytic cells to destroy the antibody after it

recognizes and binds to a foreign object

• Intracellular targeting to different organelles, eg to the

plasma membrane

What is O-linked used for?

antigenic surface of cells (blood type)

salivary receptors

T/F: everyone has the H antigen

true

A enzyme

adds an additional sugar N-acetylgalactosamine

B enzyme

adds galactose

T/F: Everyone makes antibodies that recognize type A and B. However, if you are type A, you remove the A antibody since it is “self”.

true

Type O:

for only the H antigen present; antibodies will be raised against both A and

B antigens if a patient receives blood of type A, B or AB;

Type A

for the A antigen present; antibodies will be raised against the B antigen if a

patient receives blood of type B, or AB;

Type B

for the B antigen present: antibodies will be raised against the A antigen if a

patient receives blood of type A or AB

Type AB

for both antigens present: no antibodies raised.

Universal acceptor.

T/F: For A, B, or AB, there is still some H antigen present because addition of GalNAc or Gal is incomplete, so there is no antibody raised against the H antigen.

true

Who is the universal donor?

Type O

Type A and B can donate

to their own type of to type AB

Type AB can donate to

only AB