Proper velocity Proper velocity In relativity, proper velocity, also known as celerity, is an alternative to velocity for measuring motion. Whereas velocity relative to an observer is distance per unit time where both distance and time are measured by the observer, proper velocity relative to an observer divides observer-measured distance by the time elapsed on the clocks of the traveling object. Proper velocity equals velocity at low speeds. Proper velocity at high speeds, moreover, retains many of the properties that velocity loses in relativity compared with Newtonian theory. For example, proper velocity equals momentum per unit mass at any speed, and therefore
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