How many optical isomers does isoleucine have?

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Answer 1 · 2016-10-22T14:05:42

There are four optical isomers of isoleucine.

The structure of isoleucine is

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Its chemical name is 2-amino-3-methylpentanoic acid.

We see that #"C2"# and #"C3"# are chiral centres.

The maximum number of stereoisomers is #2^n#, where #n# is the number of chiral centres.

Since #n = 2#, there are #2^n = 4# stereoisomers.

The most important stereoisomer is

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This is L-isoleucine or (#2S,3S#)-2-amino-3-methylpentanoic acid.

It is the only form that is found in nature.

The enantiomer of L-isoleucine is D-isoleucine or (#2R,3R#)-2-amino-3-methylpentanoic acid.

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Another stereoisomer is L-#allo#-isoleucine or (#2S,3R#)-2-amino-3-methylpentanoic acid.

The fourth stereoisomer is D-#allo#-isoleucine or (#2R,3S#)-2-amino-3-methylpentanoic acid.

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