Dictionary » M » Moiety



noun, plural: moieties

(general) A half or one of two approximately equal parts of something; an indefinite portion or part or share of the whole.

(chemistry) A half of a molecule; a significant segment, portion or part of a molecule that may include a substructure of the functional group.

(anthropology) One of the two descent groups from an equally divided society; each of the primary subdivisions of kin-related groups of a particular society.


In chemistry, a moiety is originally defined as half of a molecule. For example, benzyl acetate has an acetyl moiety and benzyl alcohol moiety.

Recently, moiety is used synonymously for functional group, which may be erroneous. In the example above, each moiety of benzyl acetate contains a portion of the functional group. Hence, to use moiety to mean a functional group is, therefore, inaccurate in this case.

Moiety is originally a common term in anthropology and archeology to mean the half of a tribal family. An encounter between Elizabeth Bollwerk, an archeology graduate student, and a drug research scientist led to the term's crossover.

Word origin: from the Old French meitiet (French moitié), from Latin medietas “half”, from medius “middle, half”

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Re: Kinases

You can think of an ATP as an ADP and a phosphate bound together. It is the bond between the ADP moiety and the phosphate moiety that is the highest-energy bond in the molecule. If the terminal phosphate of ATP is transferred to a protein (releasing free ADP) then the system ...

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by jonmoulton
Mon Sep 24, 2012 3:13 pm
Forum: Cell Biology
Topic: Kinases
Replies: 2
Views: 2339

Bacteria w/ Antibiotic Treatment

I think it is because the dead bacteria, which are intracellular when alive, are degraded, and their LPS (the lipid A moiety specifically) is presented on the cells to the immune system, causing an endotoxin response.

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by WntScientist
Tue Feb 14, 2012 8:12 am
Forum: Microbiology
Topic: Bacteria w/ Antibiotic Treatment
Replies: 3
Views: 3110

Effect of phosphoric acid on ATP and kinases in vitro

... pH should not change significantly. It is H3PO4 hydrolyzing to (HPO4)2- at pH around 7, which you probably use, rigth? Sure ATP has much larger moiety than just phosphate, but the kinase binds specifically the phosphate, so it should definitely work as an inhibitor

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by JackBean
Mon Mar 21, 2011 1:22 pm
Forum: Molecular Biology
Topic: Effect of phosphoric acid on ATP and kinases in vitro
Replies: 3
Views: 3634

Differentially Label

... who have different physical properties and are able to give different colors. T and U are not fluorescent by themselves, but if a fluorescent moiety is attached to them (obviously with different spectral properties) they will be easy to separate. Handy list of different fluorophores here: ...

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by canalon
Wed Feb 09, 2011 2:29 am
Forum: Molecular Biology
Topic: Differentially Label
Replies: 3
Views: 2739

Re: Electrophoresis of ionic complexes

... higher (buffer is virtually the same, but there are no reducing agents or detergents). Just in case anyone is wondering, the cationic and anionic moiety is protonated amine (polymer) and phosphate (siRNA), respectively. I can't imagine voltage may be too influential but I am just wondering if ...

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by dhkwak
Wed Jan 05, 2011 5:55 pm
Forum: Molecular Biology
Topic: Electrophoresis of ionic complexes
Replies: 6
Views: 3989
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