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.

porphyrins

natural pigments, e.g. haem, bile pigments and cytochromes
References in periodicals archive ?
While the structural changes were too insignificant to affect most of the plant's physiological functions, they did disrupt the PPO enzyme production of porphyrins and caused the enzyme-binding site to become enlarged so that the herbicide did not bind as well.
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.
In this paper, we describe a technique using UV fluorescence of porphyrins to more easily classify age of owls by examining flight feathers and molt patterns.
After all, the porphyrins are very stable compounds that have been found in "much older Esthonian fire shales" [7, 19].
The book concludes with comments on the "dilution solution to pollution" and how everything from mercury in dental fillings, to issues with fluoride, asbestos, to allowing toxins in fertilizer, provides Rochlitz with the necessary support to state that if disordered porphyrin metabolic disorders are the natural consequences of toxic exposure for some 20% of humanity, then there will never be an honest discussion of this matter.
of London) provides protocols for high-performance liquid chromotography (HPLC) and HPLC used in conjunction with mass spectrometry for analysis, identification, and characterization of porphyrins, chlorophylls, bilins, and related compounds.
Nocera s porphyrins are more efficient than existing cobalt catalysts and are made easily in two steps, so could invigorate the design of future fuel cells using cobalt over its more costly metal cousins.