Anserine (β-alanyl-''3''-methylhistidine) is a
dipeptide A dipeptide is an organic compound derived from two amino acids. The constituent amino acids can be the same or different. When different, two isomers of the dipeptide are possible, depending on the sequence. Several dipeptides are physiologicall ...
containing
β-alanine and
3-methylhistidine.
Anserine is a derivative of
carnosine
Carnosine (''beta''-alanyl-L-histidine) is a dipeptide molecule, made up of the amino acids beta-alanine and histidine. It is highly concentrated in muscle and brain tissues. Carnosine was discovered by Russian chemist Vladimir Gulevich.
Car ...
, which has been methylated.
Both anserine and carnosine are capable of chelating copper.
Due to its
methylation
In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These t ...
, anserine is more stable in serum and resistant to degradation than carnosine. Anserine can be found in the
skeletal muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
and
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
of
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s and birds.
It can also be found in high levels in the human
kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
s. The
pKa of the
imidazole
Imidazole (ImH) is an organic compound with the formula C3N2H4. It is a white or colourless solid that is soluble in water, producing a mildly alkaline solution. In chemistry, it is an aromatic heterocycle, classified as a diazole Diazole refers ...
ring of
histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...
, when contained in anserine, is 7.04, making it an effective
buffer
Buffer may refer to:
Science
* Buffer gas, an inert or nonflammable gas
* Buffer solution, a solution used to prevent changes in pH
* Buffering agent, the weak acid or base in a buffer solution
* Lysis buffer, in cell biology
* Metal ion buffer
* ...
at physiologic
pH.
Absorption and clearance
Due to its presence in lean muscles, like
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
and
poultry
Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, a ...
, there have been studies showing that inclusion of anserine in the diet may be beneficial for blood clearance and food absorption.
These results were based on
L-histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the d ...
concentrations at different time intervals.
A study observing the effect of anserine diet on blood clearance and food absorption concluded that the data showed an ephemeral anserine level peak in blood after consumption of anserine, followed by a prolonged, high level of methylhistidine.
This indicates rapid absorption and clearing of anserine because anserine is catabolized into methylhistidine and alanine by a circulating enzyme.
Clinical significance
Neuroprotective effects
An animal model study of Alzheimer's disease using mice found that treatment with anserine reduced memory loss.
Anserine reduced glial inflammatory activity (particularly of
astrocyte
Astrocytes (from Ancient Greek , , "star" + , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of endo ...
).
The study also found that anserine-treated mice had greater
pericyte
Pericytes (previously known as Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells that line the capillaries throughout the body. Pericytes are embedded in the basement membrane of blood ca ...
surface area.
The greater area of pericytes was commensurate with improved memory (pericytes warp around brain capillary to control blood flow and gate cells from neurotoxin, blocking inflammation).
The anserine-treated mice overall performed better on a spatial memory test (
Morris Water Maze
The Morris water navigation task, also known as the Morris water maze (not to be confused with ''Water maze (neuroscience), water maze''), is a behavioral procedure mostly used with rodents. It is widely used in behavioral neuroscience to study ...
).
A human study on 84 elderly subjects showed that subjects who took anserine and carnosine supplements for one year showed increased blood flow in the prefrontal cortex on MRI.
A study demonstrated that the free N-terminal of histidine on anserine and carnosine protect against zinc-caused neurotoxicity and regulate the Arc pathway in which
Arc protein is used to produce dendrite protein for connecting nerve cells.
Both Anserine and Carnosine are chelating agents for copper and other transition metals.
Chelation of transition metals is one method used by antioxidants to protect their targets from oxidative stress as it prevents them from undergoing Fenton reactions with peroxides. In the olfactory bulbs, the concentration of both of these molecules was found to be in the millimolar range, whereas the concentration of copper was approximately 50μM. these found concentrations indicate the chelation of copper by Anserine and Carnosine.
See also
*
Carnosine
Carnosine (''beta''-alanyl-L-histidine) is a dipeptide molecule, made up of the amino acids beta-alanine and histidine. It is highly concentrated in muscle and brain tissues. Carnosine was discovered by Russian chemist Vladimir Gulevich.
Car ...
References
{{reflist
Dipeptides