ˈlīˌsēn noun
( -s )
Etymology: International Scientific Vocabulary lys- + -ine; probably originally formed as German lysin
: a crystalline basic amino acid H 2 N(CH 2 ) 4 CH(NH 2 )COOH that is obtained in its dextrorotatory l form by hydrolysis of many proteins (as from blood), by fermentation, or by synthesis and resolution of the racemic form and that is essential in the nutrition of animals and man; α, ε-diamino-caproic acid