Page 113 - General Biochemistry

Chapter 7

AMINO ACIDS AND PROTEINS

Proteins are highly complex compounds that are present in all living organisms,
they are formed of monomeric units called amino acids, and there are 20
amino acids that make up proteins. These amino acids contain different
functional groups:

– Alcohols (R-OH)

– Phenol (Ph-OH)

– Carboxylic acids (R-COOH)

– Thiols (R-SH)

– Amines (R-NH2)
• Protein function depends on:

– amino acid content

– amino acid sequence.

• Protein can fold into many shapes but all information for 3-D structure is
contained in the linear sequence of amino acids.

Amino acids.

Amino acids are essentially α-amino acids:

alpha carbon (IUPAC #2 position)
H2N – C – COOH

|

R

• When R is not H, the alpha carbon is asymmetric, giving rise to isomers (L
and D), Only L-amino acids are constituents of proteins.

112