Might play a role in the regulation of methionine metabolism. Binds 1 NAD(+) per subunit. Expressed in all developmental stages from early embryo to adult (PubMed:9037110). Expressed in extended germ band embryos and in somatic mesoderm, yolk cells and midgut during late embryonic stages (PubMed:2903049). RNAi-mediated knockdown results in extended lifespan with increased fecundity and suppression of age-related decreased climbing activity and intestinal integrity (PubMed:27313316). Does not affect oxidative stress resistance (PubMed:27313316). RNAi-mediated knockdown in fat body or neurons does not show any phenotype (PubMed:27313316). Simultaneous knockdown of AhcyL1 in intestine results in extended life span (PubMed:27313316). Belongs to the adenosylhomocysteinase family. Although it belongs to the adenosylhomocysteinase family, recombinant mouse homolog AHCYL1 expressed in bacteria shows no hydrolase activity, suggesting that Drosophila AhcyL2 may also lack this activity.