| protactinium | <chemical> Protactinium. A radioactive element of the actinide group of metals. It has the atomic symbol pa, atomic number 91, and atomic weight 231. It decays by alpha-emission. Chemical name: Protactinium (12 Dec 1998) |
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| protagon | <physiology> A nitrogenous phosphorized principle found in brain tissue. By decomposition it yields neurine, fatty acids, and other bodies. Origin: Proto- + Gr. A contest. See. Protagonist. So called because it was the first definitely ascertained principle of the brain. Source: Websters Dictionary (01 Mar 1998) |
| protalbumose | Intermediate products of protein digestion, derived from hemialbumose; soluble in water and not coagulable by heat, but precipitated by ammonium sulfate, cupric sulfate, and sodium chloride. Synonym: protoalbumose. (05 Mar 2000) |
| protamin | <physiology> An amorphous nitrogenous substance found in the spermatic fluid of salmon. It is soluble in water, which an alkaline reaction, and unites with acids and metallic bases. Origin: Gr. First. Source: Websters Dictionary (01 Mar 1998) |
| protaminase | A hydrolase that releases C-terminal lysyl or arginyl residues preferentially. A zinc-containing exopeptidase. Synonym: protaminase. (05 Mar 2000) |
| protamine | Highly basic (arginine rich) protein that replaces histone in sperm heads, enabling DNA to pack in an extremely compacted form, for example clupein, iridin (4K). See: transition proteins. (18 Nov 1997) |
| protamine kinase | <enzyme> An aspect of protein kinase (ec 2.7.1.37) in which serine residues in protamines and histones are phosphorylated in the presence of ATP. Chemical name: ATP:protamine O-phosphotransferase Registry number: EC 2.7.1.70 (12 Dec 1998) |
| protamine sulfate | A purified mixture of simple protein principles from the sperm or testes of suitable species of fish; it is a heparin antagonist used in certain haemorrhagic states associated with increased amounts of heparin-like substances in the circulation and for the treatment of heparin overdosage. (05 Mar 2000) |
| protamine zinc insulin | Insulin modified by the addition of protamine and zinc chloride; it contains 40 or 80 units per ml. (05 Mar 2000) |
| protamines | <chemical> A group of simple proteins that yield basic amino acids on hydrolysis and that occur combined with nucleic acid in the sperm of fish. Protamines contain very few kinds of amino acids. Protamine sulfate combines with heparin to form a stable inactive complex; it is used to neutralise the anticoagulant action of heparin in the treatment of heparin overdose. Pharmacological action: heparin antagonists. (12 Dec 1998) |
| protandric | <zoology> Having male sexual organs while young, and female organs later in life. Protan"trism. Origin: Proto- + Gr, a man. Source: Websters Dictionary (01 Mar 1998) |
| protandrous | Having the male sex organs maturing before the female, of a flower, shedding the pollen before the stigma is receptive. Compare: protogynous. (09 Oct 1997) |
| protanomaly | A deficiency of colour perception in which the red-sensitive pigment in cones is decreased. Origin: G. Protos, first, + anomalia, anomaly (05 Mar 2000) |
| protanopia | A form of dichromatism characterised by absence of the red-sensitive pigment in cones, decreased luminosity for long wavelengths of light, and confusion in recognition of red and green. Origin: G. Protos, first, + a-priv. + ops (op-) eye (05 Mar 2000) |
| proteaceous | <botany> Of or pertaining to the Proteaceae, an order of apetalous evergreen shrubs, mostly natives of the Cape of Good Hope or of Australia. Origin: From Proteus. Source: Websters Dictionary (01 Mar 1998) |