Illustrated Glossary of Organic Chemistry
Non
acidic
amino acid
:
An
amino acid
whose side chain is neither
acidic
or
basic
.
Alanine
is a non
acidic
α-amino acid
. Its side chain (a
methyl group
) is neither
acidic
(it is not more
acidic
than
water
) nor
basic
(it does not have a nitrogen atom
lone pair
that is not
delocalized
by
resonance
).
Cysteine
is an
acidic
amino acid
because its side chain (CH
2
SH;
p
K
a
10) is more
acidic
than
wate
r (
p
K
a
15.7).
Lysine
is a
basic
amino acid
because its side chain (CH
2
CH
2
CH
2
NH
2
) has a nitrogen atom
lone pair
that is not
delocalized
by
resonance
.
Related terms:
Bronsted acid
,
Bronsted base
,
Lewis acid
,
Lewis base
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