| Biliverdin | |
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| Identifiers | |
| CAS number | 114-25-0  |
| PubChem | 251 |
| MeSH | Biliverdin |
| Properties | |
| Molecular formula | C33H34N4O6 |
| Molar mass | 582.646 |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Biliverdin is a green tetrapyrrolic bile pigment, and is a product of heme catabolism [1][2]. It is the pigment responsible for the yellowish color in bruises [2].
Contents |
Metabolism
Biliverdin results from the breakdown of the heme moiety of hemoglobin in erythrocytes. Macrophages break down senescent erythrocytes and break the heme down into biliverdin, which normally rapidly reduces to free bilirubin [1][3]. This breakdown occurs in bruises, which leads to a yellowish color [2].
Role in disease
Hepatic disease
Biliverdin has been found in excess in the blood of humans suffering from hepatic diseases. Jaundice is caused by the accumulation of biliverdin or bilirubin (or both) in the circulatory system and tissues [1]. Jaundiced skin and whites of the eyes are characteristic of liver failure.
Role in treatment of disease
While typically regarded as a mere waste product of heme breakdown, evidence has been mounting that suggests biliverdin—and other bile pigments—has a physiological role in humans [4][5].
Anti-mutagenic and anti-oxidant properties
Bile pigments such as biliverdin naturally possess significant anti-mutagenic and antioxidant properties and therefore fulfill a useful physiological function [5]. Biliverdin and bilirubin have been shown to be potent scavengers of peroxyl radicals [4][5]. They have also been shown to inhibit the effects of polycyclic aromatic hydrocarbons, heterocyclic amines, and oxidants—all of which are mutagens. Studies have even found that people with higher concentrations levels of bilirubin and biliverdin in their bodies have a lower frequency of cancer and cardiovascular disease [4].
Possible use as a protease inhibitor
A 1996 study by McPhee et al. suggested that biliverdin—as well as many other tetrapyrrolic pigments—may function as an HIV-1 protease inhibitor. Of the fifteen compounds tested, biliverdin was one of the most active. In vitro experiments showed that biliverdin and bilirubin competitively inhibited HIV-1 proteases at low macromolar concentrations, reducing viral infectivity. However, when tested in cell culture with macromolar concentrations, it was found that biliverdin and bilirubin reduced infectivity by blocking viral entry into cells. Results were found to be similar for HIV-2 and SIV. Further research is needed to confirm these results, and to examine if unconjugated hyperbilirubinemia has any effect on the progression of HIV infection [6].
Possible use in treatment of asthma
Current research has suggested that the anti-oxidant properties of biliverdin and other bile pigments may also have a beneficial effect on asthma. This is because oxidative stress may play a vital role in the pathogenesis of asthma. A 2003 study found that asthma patients suffering from jaundice brought on by acute hepatitis B exhibited temporary relief of asthma symptoms. However, there could also have been confounding factors such as elevated levels of cortisol and epinephrine, so more research into this possibility is required [5].
In non-human animals
Biliverdin is an important component of avian egg shells. There is a significantly higher concentration of biliverdin in blue egg shells than in brown egg shells. Research has shown that the biliverdin of egg shells is produced from the shell gland, rather than from the breakdown of erythrocytes in the blood stream. The presence of biliverdin in egg shells may be an indicator of female fitness, and therefore is likely evolutionarily important [7].
Along with its presence in avian egg shells, other studies have also shown that biliverdin is present in the blue-green blood of many marine fish, the blood of tobacco hornworm, the wings of moth and butterfly, the serum and eggs of frogs, and the placenta of dogs [8]. In the garfish (Belone belone) and related species, the bones are bright green because of biliverdin.
Biliverdin is also present in the green blood, muscles, bones, and mucosal lining of skinks of the genus Prasinohaema, found in New Guinea. It is uncertain whether this presence of biliverdin is an ecological or physiological adaptation of any kind. It has been suggested that accumulation of biliverdin might deter harmful infection by Plasmodium malaria parasites, though no statistically significant correlation has been established [9]. The Cambodian frog, Chiromantis samkosensis also exhibits this character along with turquoise bones.[10]
In fluorescence imaging
In a complex with reengineered bacterial phytochrome, biliverdin has been employed as IR-emitting chromophore.[11] This was the first example of genetically encoded IR-emitting probe. In contrast to fluorescent proteins which form their chromophore through postranslational modifications of the polypeptide chain, phytochromes require an external ligand (in this case, biliverdin). While biliverdin supplements have been shown to be beneficial for the imaging contrast, for many applications the amounts of BV produced naturally are sufficient.
See also
References
- ^ a b c Boron W, Boulpaep E. Medical Physiology: a cellular and molecular approach, 2005. 984-986. Elsevier Saunders, United States. ISBN 1-4160-2328-3
- ^ a b c Mosqueda L, Burnight K, Liao S (2005). “The Life Cycle of Bruises in Older Adults”. Journal of the American Geriatrics Society. 53(8):1339-1343. DOI:10.1111/j.1532-5415.2005.53406.x
- ^ Seyfried H, Klicpera M, Leithner C, Penner E (1976). “Bilirubin metabolism”. Wien Klin Wochenschr. 88:477-82. PMID: 793184
- ^ a b c Bulmer AC, Ried K, Blanchfield JT, Wagner KH (2008). “The anti-mutagenic properties of bile pigments”. Mutat Res. 658(1-2):28-41. PMID: 17602853
- ^ a b c d Ohrui T, Yasuda H, Yamaya M, Matsui T, and Sasaki H (2003). “Transient Relief of Asthma Symptoms during Jaundice: A Possible Beneficial Role of Bilirubin”. Tohuku J. Exp. Med. 199: 193-196. PMID: 12703664
- ^ McPhee F, Caldera P, Bemis G, McDonagh A, Kuntz I, and Craik C (1996). “Bile pigments as HIV-1 protease inhibitors and their effects on HIV-1 viral maturation and infectivity in vitro”. Biochem. J. 320: 681–686 PMID: 8973584
- ^ Zhao R, Xu GY, Liu ZZ, Li JY, Yang N (2006). “A study on eggshell pigmentation: biliverdin in blue-shelled chickens”. Poult Sci. 85(3):546-9. PMID: 1655328
- ^ Fang LS, Bada JL (1990). “The blue-green blood plasma of marine fish”. Comp Biochem Physiol B. 97(1):37-45. PMID: 2253479
- ^ Austin C, Perkins S (2006). “Parasites in a biodiversity hotspot: a survey of hematozoa and a molecular phyolgenetic analysis of plasmodium in New Guinea skinks”. Journal of Parasitology 92(4):770-777. doi: 10.1645/GE-693R.1
- ^ Lee Grismer, L. (2007). "A New Species of Chiromantis Peters 1854 (Anura: Rhacophoridae) from Phnom Samkos in the Northwestern Cardamom Mountains, Cambodia". Herpetologica 63: 392. doi:.
- ^ X. Shu et al. (2009). "Mammalian Expression of Infrared Fluorescent Proteins Engineered from a Bacterial Phytochrome". Science 324: 804-807. doi:.
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