Cysteine is formed from
Serin+Homocystein ------->Cysteine+Homoserin.Homocystein is synthesized from Methionine.Ref: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 217, Fig no 16.15
Methionine and serine
Methionine and glycine
Alanine and glycine
Serine and glycine
Metabolism of protein and amino acid