Jack and Jill (nursery rhyme) these stanzas were viewed as quatrains with internal rhymes, this would be an example of ballad form, a common form for nursery rhymes. The melody commonly associated with the rhyme was first recorded by the composer and nursery rhyme collector James William Elliott in his "National Nursery Rhymes and Nursery Songs" (1870). The Roud Folk Song Index, which catalogues folk songs and their variations by number, classifies the song as 10266. The phrase "Jack and Jill" was in use in England as early as the 16th century to indicate a boy and a girl. A comedy with the title "Jack
S-ribosylhomocysteine lyase S-ribosylhomocysteine lyase In enzymology, a S-ribosylhomocysteine lyase () is an enzyme that catalyzes the chemical reaction Hence, this enzyme has one substrate, S-(5-deoxy-D-ribos-5-yl)-L-homocysteine, and two products, L-homocysteine and (4S)-4,5-dihydroxypentan-2,3-dione. This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is S-(5-deoxy-D-ribos-5-yl)-L-homocysteine L-homocysteine-lyase [(4S)-4,5-dihydroxypentan-2,3-dione-forming]. Other names in common use include S-ribosylhomocysteinase, and LuxS. This enzyme participates in methionine metabolism. Furthermore, LuxS is involved in the synthesis of autoinducer AI-2 (autoinducer-2), which plays a role in quorum sensing in a certain number of bacterial species. LuxS converts S-ribosylhomocysteine to homocysteine and