n. [ Gr. prw^tos first. ] (Physiol. Chem.) An older, imprecise term replaced by protein.
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]

‖n. pl. [ NL. See Proteus, and -oid. ] (Zool.) An order of aquatic amphibians having prominent external gills and four legs. It includes Proteus and Menobranchus (Necturus). Called also Proteoidea, and Proteida. [ 1913 Webster ]

a. (Zool.) Changeable in form; resembling a Proteus, or an amœba. [ 1913 Webster ]

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. 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 ]

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. ]

a. (Physiol. Chem.) Of or related to protein; albuminous; proteid. [ 1913 Webster ]

a. Proteinaceuos. [ 1913 Webster ]