Biomaterial Database

Spectroscopic properties of tetrapyrroles on denatured biliproteins. 1984

D Guard-Friar, and R MacColl

Four biliproteins (phycoerythrin 545, phycocyanin 612, phycocyanin 645, and C-phycocyanin) were denatured by a high concentration of urea and then studied by absorption spectroscopy. Low pH and high protein concentrations conserved the tetrapyrroles' color, and mercaptoethanol and dithiothreitol promoted bleaching. One of these tetrapyrroles, cryptoviolin, appeared not to be hypochromic in the presence of depleting phycocyanobilin, but its absorbance did decay when phycocyanobilin is absent. The product from the treatment of phycocyanobilin with mercaptoethanol or dithiothreitol overlapped spectrally with cryptoviolin and gave the false appearance of maintaining a constant cryptoviolin concentration. Failure to note this effect could result in erroneous cryptoviolin/phycocyanibilin ratios.

UI	MeSH Term	Description	Entries
D008623	Mercaptoethanol	A water-soluble thiol derived from hydrogen sulfide and ethanol. It is used as a reducing agent for disulfide bonds and to protect sulfhydryl groups from oxidation.	2-ME,2-Mercaptoethanol,2 Mercaptoethanol
D010798	Phycocyanin	The metal-free blue phycobilin pigment in a conjugated chromoprotein of blue-green algae. It functions as light-absorbing substance together with chlorophylls.	C-Phycocyanin,C Phycocyanin
D010799	Phycoerythrin	The metal-free red phycobilin pigment in a conjugated chromoprotein of red algae. It functions as a light-absorbing substance together with chlorophylls.
D010860	Pigments, Biological	Any normal or abnormal coloring matter in PLANTS; ANIMALS or micro-organisms.	Biological Pigments
D011489	Protein Denaturation	Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.	Denaturation, Protein,Denaturations, Protein,Protein Denaturations
D011758	Pyrroles	Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.	Pyrrole
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D013053	Spectrophotometry	The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol
D045725	Tetrapyrroles	Four PYRROLES joined by one-carbon unit linking position 2 of one to position 5 of the next. The conjugated bond system results in PIGMENTATION.	Tetrapyrrole