The key difference between melanin and circadin is that melanin is a type of pigment that forms in animal cells, whereas circadin is a type of hormone that forms in animals, plants, and microorganisms.
Melanin and circadin are organic compounds. Circadin is the trade name for the melatonin hormone. Although the names melanin and melatonin sound related, they are two different components that form in living organisms.
CONTENTS
1. Overview and Key Difference
2. What is Melanin
3. What is Circadin
4. Melanin vs Circadin in Tabular Form
5. Summary – Melanin vs Circadin
What is Melanin?
Melanin is a group of natural pigments we can find in many organisms. This pigment produces through a chemical process having several steps, and this process is named melanogenesis. In this process, oxidation of the amino acid tyrosine occurs, followed by a polymerization reaction. This production of melanin pigments occurs in a specific group of cells named melanocytes.
Figure 01: Chemical Structure of Melanin
We can identify five basic types of melanin molecules known as eumelanin, pheomelanin, neuromelanin, allomelanin and pyomelanin. Among these types, the most common melanin pigment type is eumelanin, which also has two subcategories known as brown eumelanin and black eumelanin. Moreover, pheomelanin is a derivative of cysteine, and it contains polybenzothiazine. Neuromelanin can be found in the brain. Allomelanin and pyromelanin are nitrogen-free melanin pigments.
What Does Melanin Do?
The production of melanin in the human skin initiates with the exposure of the skin to UV radiation. This melanin production causes the skin to get darkened. However, melanin is an effective absorbent of light where the pigment is able to dissipate about 99% of the absorbed UV radiation. This property of melanin makes us believe that it can protect our skin from UV radiation damage, which can reduce the risk of folate depletion and dermal degradation.
In addition, melanin can act as an antioxidant, and its antioxidant ability is directly proportional to the degree of polymerization. According to some research studies, melanin exists in support of a highly cross-linked heteropolymer that is bound covalently to matrix scaffolding melanoproteins.
What is Circadin?
Circadin is the trade name for melatonin, which is a hormone released from the pineal gland at night and is associated with the sleep-wake cycle (read: circadian rhythm). Often, it is included in dietary supplements that are useful for the short term treatment of insomnia. There are some common side effects of this medication which include sleepiness, headache, nausea, diarrhoea, irritability, anxiety, migraine, lethargy, etc.
Figure 2: Biosynthesis of Circadin
When considering the biosynthesis of circadian, it is produced in animals through hydroxylation, decarboxylation, acetylation, and methylation, which starts with L-tryptophan. Moreover, L-tryptophan forms in the shikimate pathway from chorismite. We can also acquire it from protein catabolism. However, in small organisms such as bacteria, fungi, and in some plants, this pigment forms indirectly with tryptophan existing as an intermediate product of the shikimate pathway. There, the synthesis starts with D-erythrose 4-phosphate and phosphoenolpyrivate.
What is the Difference Between Melanin and Circadin?
Melanin and circadin are organic compounds. The key difference between melanin and circadin is that melanin is a type of pigment that forms in animal cells, whereas circadin is a type of hormone that forms in animals, plants, and microorganisms. Moreover, the melanin absorbs UV radiation while circadin is helpful in the sleep-wake cycle.
The following infographic presents the difference between melanin and circadin in tabular form.
Summary – Melanin vs Circadin
Melanin and circadin are organic compounds. The key difference between melanin and circadin is that melanin is a type of pigment that forms in animal cells, whereas circadin is a type of hormone that forms in animals, plants, and microorganisms.
Reference:
1. Glagoleva, Anastasiia Y., et al. “Melanin Pigment in Plants: Current Knowledge and Future Perspectives.” Frontiers, Frontiers.
Image Courtesy:
1. “Melanin” By ClickChemist – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Melatonin biosynth” By Adricorr7 (talk) – Own work (Public Domain) via Commons Wikimedia