Secreted enzyme that regulates the endogenous N-fatty acyl amino acid (NAAs) tissue and circulating levels by functioning as a bidirectional NAA synthase/hydrolase. It condenses free fatty acids and free amino acids to generate NAAs and bidirectionally catalyzes the reverse hydrolysis reaction. Some of these NAAs stimulate oxidative metabolism via mitochondrial uncoupling, increasing energy expenditure in a UPC1-independent manner. Thereby, this secreted protein may indirectly regulate whole body energy expenditure. PM20D1 circulates in tight association with both low- and high-density (LDL and HDL,respectively) lipoprotein particles. an N-acyl-L-amino acid + H2O = a carboxylate + an L-alpha-amino acid an N-acyl-aromatic L-alpha-amino acid + H2O = a carboxylate + an aromatic L-alpha-amino acid H2O + N-(5Z,8Z,11Z,14Z)-eicosatetraenoyl-glycine = (5Z,8Z,11Z,14Z)-eicosatetraenoate + glycine H2O + N-hexadecanoyl-L-phenylalanine = hexadecanoate + L-phenylalanine H2O + N-octadecanoyl-L-phenylalanine = L-phenylalanine + octadecanoate H2O + N-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-L-phenylalanine = (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + L-phenylalanine H2O + N-(9Z-octadecenoyl)-L-asparagine = (9Z)-octadecenoate + L-asparagine (9Z)-octadecenoate + glycine = H2O + N-(9Z-octadecenoyl)glycine H2O + N-(9Z-octadecenoyl)-L-lysine = (9Z)-octadecenoate + L-lysine H2O + N-(9Z-octadecenoyl)-L-methionine = (9Z)-octadecenoate + L-methionine H2O + N-(9Z-octadecenoyl)-L-serine = (9Z)-octadecenoate + L-serine H2O + N-(9Z-octadecenoyl)-L-tryptophan = (9Z)-octadecenoate + L-tryptophan H2O + N-(9Z-octadecenoyl)-L-tyrosine = (9Z)-octadecenoate + L-tyrosine H2O + N-(9Z-octadecenoyl)-L-glutamine = (9Z)-octadecenoate + L-glutamine H2O + N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-L-serine = (5Z,8Z,11Z,14Z)-eicosatetraenoate + L-serine (5Z,8Z,11Z,14Z)-eicosatetraenoate + L-phenylalanine = H2O + N-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-L-phenylalanine H2O + N-(9Z-octadecenoyl)-L-leucine = (9Z)-octadecenoate + L-leucine (9Z)-octadecenoate + L-phenylalanine = H2O + N-(9Z-octadecenoyl)-L-phenylalanine Binds 2 Zn(2+) ions per subunit. Lipoproteins are powerful coactivators of PM20D1 activity in vitro and NAA biosynthesis in vivo. Amino-acid metabolism. Energy metabolism; electron transfer. Lipid metabolism; fatty acid metabolism. Belongs to the peptidase M20A family.