what;s the unusual physical properties of alanine?

Answer 1

There are two.
1. It's the simplest amino acid to show enantiomerism.
2. Its melting point will be much higher than predicted due to it existing in its zwitterionic form in the solid.

Answer 2

Alanine (Ala, A) also 2-aminopropanoic acid is a non-essential α-amino acid. It exists as two distinct enantiomers - L-alanine and D-alanine. L-alanine is one of the 20 amino acids most widely used in protein synthesis, second to leucine, accounting for 7.8% of the primary structure in a sample of 1,150 proteins [1]. D-alanine occurs in bacterial cell walls and in some peptide antibiotics.

The α-carbon atom of alanine is bound with a methyl group (-CH3), making it one of the simplest α-amino acids with respect to molecular structure and also resulting in alanine being classified as an aliphatic amino acid.

Alanine is most commonly made by transfer of an amine group to pyruvate. Because transamination reactions are readily reversible, alanine can be easily formed from pyruvate and thus has close links to metabolic pathways such as glycolysis, gluconeogenesis, and the citric acid cycle.