Question

Give reason for tears start flowing while cutting onions.

Answer 1

Onion contains the amino acid sulfoxides as well as, it also contains an enzyme called lachrymatory factor synthase. When we cut an onion, then lachrymatory factor synthase is released into the air. It converts the amino acid sulfoxide of the onion into sulfenic acid, it is a very unstable compound. The unstable sulfenic acid rearranges itself into syn- propanethial-S-oxide. Syn-propanethial-S-oxide gets into the air and comes in contact with our eyes. The lachrymal gland becomes irritated and produces the tears.