Search results
Results From The WOW.Com Content Network
Drug precursors, also referred to as precursor chemicals or simply precursors, are substances used to manufacture illicit drugs. Most precursors also have legitimate commercial uses and are legally used in a wide variety of industrial processes and consumer products, such as medicines, flavourings, and fragrances.
In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry , the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway , such as a protein precursor .
Precursors in the Halo series, an extremely advanced race that preceded and were destroyed by The Forerunners; Precursor, a 1999 novel set in C. J. Cherryh's Foreigner universe; Precursors, a fictional race (now extinct) of ancient beings in the board game Cosmic Encounter; Precursors, a fictional alien race in the Star Control video game series
In biochemistry, a zymogen (/ ˈ z aɪ m ə dʒ ən,-m oʊ-/ [1] [2]), also called a proenzyme (/ ˌ p r oʊ ˈ ɛ n z aɪ m / [3] [4]), is an inactive precursor of an enzyme.A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) for it to become an active enzyme.
The sentence can be given as a grammatical puzzle [7] [8] [9] or an item on a test, [1] [2] for which one must find the proper punctuation to give it meaning. Hans Reichenbach used a similar sentence ("John where Jack had...") in his 1947 book Elements of Symbolic Logic as an exercise for the reader, to illustrate the different levels of language, namely object language and metalanguage.
NMN is the immediate precursor to NAD+ in the salvage pathway. [39] Besides assembling NAD + de novo from simple amino acid precursors, cells also salvage preformed compounds containing a pyridine base. The three vitamin precursors used in these salvage metabolic pathways are nicotinic acid (NA), nicotinamide (Nam) and nicotinamide riboside (NR ...
The particular type of precursor characterized by increasing period and amplitude is known as the high-frequency Sommerfeld precursor. In a region of anomalous dispersion, where low-frequency components have faster group velocities than high-frequency ones, the opposite of the above situation occurs: the onset of the precursor is characterized ...
Protein precursors are often used by an organism when the subsequent protein is potentially harmful, but needs to be available on short notice and/or in large quantities. Enzyme precursors are called zymogens or proenzymes. Examples are enzymes of the digestive tract in humans. Some protein precursors are secreted from the cell.