protein

(pro'te-in) [G. protos, first.] One of a group of substances constituting the greater part of animal and vegetable ti ues; they are formed chiefly by plants. They are of very complex constitution, all containing carbon, hydrogen, nitrogen, and oxygen, and some containing in addition iron, phosphorus, or sulphur; chemically they are regarded as peptides (poljrpeptides) or combinations of amino acids and their derivatives. They are colorle , odorle , in general tastele , and of. varying degrees of solubility; they are putrefiable and readily undergo chemical change, hydrolysis, under the influence of ferments and. on boiling with dilute acids or alkalies, al'coholsol'uble p., gliadin, a simple protein, found in grain, soluble in 70 to 80 per cent alcohol and in dilute acids and alkalies, but not in absolute alcohol or neutral solvents, autol'ogous any p. found normally in the fluids or ti ues of the body, coag'ulated p., an insoluble product formed by the action of heat on p.; hard-boiled white of egg is an example. com'pound p., conjugated p. con'jugated p., a substance which contains the protein molecule united to some other molectde or molecules otherwise than as a salt; the group contains the nucleoproteins, glycoproteins, phos php proteins, lecithoproteins, and chromoproteins or hemoglobins, defen's ive p., an antibody, alexin, phylaxin. derived p., a derivative of the protein molecule effected by hydrolysis in the primary protein derivatives (meta proteins, acid and alkali proteins or albumins) there has been only a slight change in the protein molecule; the secondary protein derivatives (proteoses, peptones) are the products of more extensive cleavage of the protein molecule through hydrolysis, floating p., one present in the body fluids but not entering into the formation of the ti ues, for'eign p., one which differs from any contained in the blood, lymph, or ti ues of the body, heterol'ogous p., foreign p. immune p., antitoxin, protect'ive p., defensive p. pyocyan'ic p., a remedy used in certain forms of suppuration, obtained by treating cultures of Bacillus pyocyaneus with pota a. simple p., one which yields only a-amino acids or their derivatives by hydrolysis; the group contains albumins, globulins, glutelins, alcohol soluble proteins, albuminoids, histones, and protamines.