Page 158 - The Manga Guide to Biochemistry

Because of this difference in structure, α-amylase, which can break down α(1→4)
glycosidic bonds, is unable to break down β(1→4) glycosidic bonds.

Cellulose

β(1→4)

α-amylase

Can break Starch
this down!
α(1→4)

Wow! That twisted connection really makes a big difference!

So cellulose, which is formed by β(1→4) glycosidic bonds, is not broken down in
our digestive system. This makes it very effective as dietary fiber. It...you know...
keeps you regular.

Well. Moving right along! Remember when we were talking about sucrose in fruit?
We discovered that sucrose is made up of one glucose and one fructose connected
together. The carbon at position 1 of glucose is connected to the carbon at position 2
of fructose, as you can see below.

o O
j
n OH o O OH

m jn k →O
O α(1 2)
m l jCH2OH glycosidic
l k OH
Fructose bond
Glucose
k

CH2OH

Sucrose

I get it! So sucrose is formed with an α(1→2) glycosidic bond, right?

Exactly! And now that you know how individual monosaccharides are connected
together, you should have a much better understanding of why these substances
have their unique physical properties.

144 Chapter 3