Cysteine is synthesized from
Methionine is first conveed to active methionine and then it is conveed to cysteine on combining with serine.Ref: DM Vasudevan - Textbook of Biochemistry, 7th edition, page no: 217, Fig 16.14, 16.15.
Methionine
Arginine
Histidine
Lysine
Metabolism of protein and amino acid