porphyrins


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Related to porphyrins: porphyria, Apolipoproteins

por·phy·rins

(pōr'fi-rinz),
Pigments widely distributed throughout nature (for example, heme, bile pigments, cytochromes) consisting of four pyrroles joined in a ring (porphin) structure. They are substitution products of porphin (porphyrin) and comprise several varieties, differing for the most part in the side chains (for example, methyl, ethyl, vinyl, formyl, carboxyethyl, carboxymethyl) present at the eight available positions on the pyrrole rings. Depending on the nature of the side chains, the prefixes deutero-, etio-, meso-, proto-, etc., are attached to porphyrins. Distribution within each class is by types I, II, III, or IV. Porphyrins combine with various metals (for example, iron, copper, magnesium) to form metalloporphyrins, and with nitrogenous substances.

por·phy·rins

(pōr'fir-inz)
Pigments widely distributed throughout nature (e.g., heme, bile pigments, cytochromes) consisting of four pyrroles joined in a ring (porphin) structure.
References in periodicals archive ?
The study showed the patient's blood and right hemispheric dominance had increased heme oxygenase activity and porphyrins.
I] porphyrins are able to react with alkyl or aryl halides (RX) to form [sigma]-bonded [Fe.
In a variety of synthetic porphyrins, the water-soluble porphyrins are of particular interest.
Since the porphyrin group--derived from chlorophyll--is optically active, incorporating the porphyrin-phospholipid into the liposome should have allowed it to react with light.
163 ("Alfred Treibs found porphyrins in early 1930's in very ancient Esthonian fire shales").
Techniques that may be involved are measuring porphyrins in amniotic fluid and amniotic cell culture1.
Oral activated charcoal and cholestyramine are used to retard and prevent reabsorption of endogenous porphyrins.
The purpose of this poster is to analyze their synergetic disruption of porphyrin metabolism to better understand risks associated with their exposure.
ZettaCores porphyrins are "at least as fast as current memory devices," said Levine, the company's president and CEO "Number two, these (molecules) require less power than traditional memory.
The UV-Visible absorption spectra of free-base and nickel porphyrins have been investigated in binary mixtures of solvents with similar polarities and dissimilar refractive indices.
Porphyrins themselves contain four benzene groups connected by coordination bonds to a metal ion (Fe, Mg, Mn, etc) in the center.