Variable-mass system events. The following derivation is for a body that is gaining mass (accretion). A body of time-varying mass "m" moves at a velocity v at an initial time "t". In the same instant, a particle of mass dm moves with velocity u. The initial momentum can be written as Now at a time "t" + d"t", let both the main body and the particle accrete into a body of velocity v + dv. Thus the new momentum of the system can be written as Since d"m"dv is the product of two small values, it can be ignored, meaning during d"t"
N,N-Dimethyltryptamine (step 1). The resulting decarboxylated tryptophan analog is tryptamine. Tryptamine then undergoes a transmethylation (step 2): the enzyme indolethylamine-N-methyltransferase (INMT) catalyzes the transfer of a methyl group from cofactor S-adenosyl-methionine (SAM), via nucleophilic attack, to tryptamine. This reaction transforms SAM into S-adenosylhomocysteine (SAH), and gives the intermediate product "N"-methyltryptamine (NMT). NMT is in turn transmethylated by the same process (step 3) to form the end product "N","N"-dimethyltryptamine. Tryptamine transmethylation is regulated by two products of the reaction: SAH, and DMT were shown "ex vivo" to be among the most potent inhibitors of rabbit INMT activity. This transmethylation mechanism has been