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The Collaborative International Dictionary of English v.0.48 (gcide)

Protein \Pro"te*in\, n. (Physiol. Chem.)
In chemical analysis, the total nitrogenous material in
vegetable or animal substances, obtained by multiplying the
total nitrogen found by a factor, usually 6.25, assuming most
proteids to contain approximately 16 per cent of nitrogen.
[Webster 1913 Suppl.]


Proteid \Pro"te*id\, n. [Gr. prw^tos first.] (Physiol. Chem.)
An older, imprecise term replaced by {{protein}}.

Note: Proteid was defined in the 1913 Webster as "One of a
class of amorphous nitrogenous principles, containing,
as a rule, a small amount of sulphur; an albuminoid, as
blood fibrin, casein of milk, etc. Proteids are present
in nearly all animal fluids and make up the greater
part of animal tissues and organs. They are also
important constituents of vegetable tissues. See 2d
Note under {Food}." -- {Pro"te*id}, a.

Syn: protein.
[1913 Webster PJC]

{Defensive proteid} (Physiol. Chem.), one of a class of
proteid substances, present in some animal tissues and
fluids, that make the body immune to certain infectious
diseases by destroying or rendering inactive the toxic
products of bacterial growth; -- this is an older term
replaced by more precise modern immunological concepts
such as {antibody} and {immunoglobulin}. [archaic]
[Webster 1913 Suppl. PJC]


Protein \Pro"te*in\, n. [Gr. prw^tos first: cf. prwtei^on the
first place.] (Physiol. Chem.)
any polymer of an amino acid joined by peptide (amide) bonds.
Most natural proteins have alpha-amino acids as the monomeric
constituents. All classical enzymes are composed of protein,
and control most of the biochemical transformations carrie
dout in living cells. They may be soluble, as casein,
albumins, and other globular proteins, or insoluble (e. g.
"structural proteins"), as collagen or keratin. "albumin", an
older term for protein, is now used primarily to refer to
certain specific soluble globular proteins found in eggs or
blood serum, e.g. {bovine serum albumin}, the main soluble
protein in teh serum of cattle, used as an enzymatically
inert protein in biochemical research.

Note: In the 1913 dictionary, protein was defined as: "A body
now known as alkali albumin, but originally considered
to be the basis of all albuminous substances, whence
its name."
[1913 Webster PJC]

{Protein crystal}. (Bot.) See {Crystalloid}, n., 2.
[1913 Webster]


macromolecule \mac`ro*mol"e*cule\, n. (Chem., Biochem.)
A very large molecule, especially a polymer having from
hundreds to many thousands of atoms, such as {DNA}, {RNA},
{protein}, {polysaccharide}, {polyethylene}, {polycarbonate},
etc.
[PJC]