The branch amino acids involved in “the hypothesis of plasma amino acid imbalance” include A: Valine, leucine and isoleucine B: Valine, leucine and tyrosine C: Leucine, isoleucine and phenylalanine D: Tyrosine and phenylalanine E: Valine, tyrosine and phenylalanine

Whichone<br/>is<br/>the essential amino acid?() A: glycine B: methionine C: tyrosine D: Glutamine

In plants and bacteria, phenylalanine and tyrosine are synthesized from chorismate in pathways much more complex than the tryptophan pathway.

以下哪些为必需氨基酸（） A: methionine B: valine C: isoleucine D: cystein E: tyrosine

Which one of the<br/>following amino acids can be phosphorylated? () A: Tyrosine B: Alanine C: Aspartate D: Methionine E: Glutamine