L’acid aspartico (Asp) – ionic form: aspartate – it’s a amino acid (AA) not essential for the human organism.
L’enantiomero “L-Aspartic acid is one of 22 amino acids proteinogenici – involved in protein synthesis.
Il D-aspartate (DAA), an isomer non proteinogenic and come on limited biological rolesis one of the two D-amino acids which can normally be found in the mammalian organism.
L-aspartic acid is abundantly ingested in the diet due to its widespread presence in dietary proteins – in some more than others.
Aspartic acid is also available as dietary supplement, in various forms. D-aspartic acid is proposed as a testosterone booster but, as we will see, its usefulness is more than controversial.
Use: increased testosterone can have both a positive effect on male libido and erection, and on increasing muscle anabolic potential.
What is aspartic acid used for?
L-aspartic acid plays many biological roles in the human body, which we are going to list below:
- is one of the “building blocks” that make up peptides and proteins (protein synthesis). It therefore participates in all the biological roles attributable to these bio-macro-molecules (contractile tissue, structural tissue, transport and reserve proteins, immunoglobulins, hemostatic factors, hormones, enzymes, membrane channels, intracellular signalers, etc.);
- plays a role in cycle dell’urealike ammonia, donating amino groups which lead to the formation of urea;
- participate in gluconeogenesi;
- Carries reducing equivalents as a vector malate-aspartate – oxidized (dehydrogenated) derivative of malic acid – using the interconversion between aspartate and oxaloacetate;
- donates a nitrogen atom to the biosynthesis dell’inosinathe precursor of purine bases;
- acts as a hydrogen acceptor in a chain ATP synth;
- dietary L-aspartic acid acts as a inhibitor from the beta-glucuronidationthat regulates the enterohepatic circulation of bilirubin and bile acids;
- aspartate stimulates NMDA receptors – although not as strongly as the amino acid neurotransmitter L-glutamate.
Where is aspartic acid found?
We reiterate that aspartic acid non it is an amino acid essentialwhich means that it can be normally synthesized by the human body.
However, aspartic acid it is abundantly present in the diet omnivorous.
The foods richest in aspartic acid are those of animal origin; some examples are: fishery products (especially oysters), carne – both white and red – but also processed (cured meats and sausages), game, etc.;
However, it is present in many plant sources, such as i sprouted seeds, oatmeal, avocado e asparagussugar cane sprouts and molasses of sugar beet etc.
Il aspartame sweetener it is formed by aspartic acid, phenylalanine, trimer of formaldehyde.
Aspartic acid and aspartate supplements
Both aspartic acid and its salts can be integrated with specific products.
However, some products, while containing aspartate, are not designed to increase dietary levels of this amino acid. For example, magnesium aspartate has the function of increasing the intake of magnesium in a plus form bioavailablebecause it’s organic.
The molecule most involved in the formulation of food supplements based on the specific role of the amino acid in question is the acid D-asparticoi.e. the isomer with minor biological roles compared to the more widespread L-aspartic acid.
The alleged effects of the acid D-aspartico would be of improvement of the sex hormones and, more precisely, of testosterone.
Experimentally, D-aspartic acid appears to have increased testosterone (T) levels in two different, independent studies.
One on healthy males reported a 42% increase in T levels (dosage 3.12 g/day), another on men infertile and suffering from severe methodological limitations, reported a 30-60% increase in T (dosage 2.66 g/day). g/day).
On the other hand, later studies performed on males train they did not appreciate any increase in T (dosage 3.00 g/day). The last one carried out even highlighted a decrease of 12.5% T (dosage 6.00 g/day).
From the evidence, it is possible that DAA could improve testosterone production in men with low levels of the same, but not in healthy and trained men..
Therefore, on the one hand supplementation with D-aspartic acid “could” pay off useful in the improvement of libido and oferection in case of real problems. On the other hand, when taken to increase muscle mass in the context of full health and function – testosterone is a major anabolic hormone – D-Aspartic Acid could potentially be useless.
It is not known if taking DAA under conditions unfavorable for the production of T in healthy even trained subjects, such as very low percentages of fat mass or overtraining or other, can in some way be positive on the levels of the same.
How much aspartic acid or aspartate to take?
The useful dosage of D-aspartic acid can fluctuate, as evidenced by previous studies, from just over 2.5 g / day to 3.0 g / day; higher doses have proved not only useless, but even counterproductive.
When to take aspartic acid or aspartate?
D-aspartic acid can be taken both on an empty stomach and in conjunction with meals, since it does not present alterations in absorption, and because the D- isomer is not used in normal metabolic processes which instead affect the L- enantiomer .
Wanting to identify a “hypothetically” best time to try to increase testosterone levels in the body, the choice could be oriented towards:
- pre-, peri- or post-workout for strength and hypertrophy, in order to optimize the natural secretion of the same induced by specific training;
- before night sleep (before bedtime), in order to optimize its natural secretion at the time of day when, according to circadian rhythms, it should reach its physiological peak.
However, these are mere guesses.
Biosynthesis of aspartic acid
Level geneticaspartic acid is encoded by codons GAU e GAC.
The enzymatic synthesis of aspartic acid can give rise to both isomers, creating a so-called racemic mixture (mister).
In the human body, aspartate is most frequently produced through the transamination dell’oxaloacetate.
The biosynthesis of aspartate is facilitated by an enzyme known as aminotransferasiwhich transfers to oxaloacetate an amino group from a donor molecule – such as alanine or glutamine – and thus producing a molecule of aspartate and one of alpha-cheto acid.
In microorganisms and plants
In plants and microorganisms, aspartate is the precursor of numerous amino acids, including four essential for humans: methionine, threonine, isoleucine e lysine.
The conversion of aspartate to these other amino acids begins with the reduction of aspartate to its “semialdehyde”, O2CCH(NH2)CH2CHO.
Asparagine is derived from transamination from aspartate:
-O2CCH(NH2)CH2CO2- + GC(O)NH3+ O2CCH(NH2)CH2CONH3+ + GC(O)O
(where GC(O)NH2 and GC(O)OH are glutamine and glutamic acid, respectively).
Aspartic acid in biochemistry
Aspartic acid (symbol Asp o D) it’s a a-amino acid with ionic form known as aspartate.
Under physiological conditions, it possesses a group α-amino NH3+ (protonated), while the acid group α-carbossilico is a COO– (deprotonated).
Aspartic acid has a acid side chain (CH2COOH) which reacts with other amino acids, enzymes and proteins.
Under physiological conditions (a pH 7,4), usually the negatively charged aspartate COO– forms the side chain of proteins.
Its side groups are often hydrogen bonded to form asx turns o asx patternsmost often at the N-termini of alpha-helical secondary structures.
Like glutamic acid, aspartic acid is also classified as an amino acid acidwith a pKa Of 3,9; on the other hand, in peptides this parameter strongly depends on the local environment, and could rise up to 14.
Historical notes on aspartic acid
Aspartic acid was discovery for the first time in 1827 and Auguste-Arthur Plisson e Etienne Ossian Henrythrough the hydrolysis ofasparaginaitself isolated from asparagus juice in 1806.
The method initially employed exploited lead hydroxide, but today other acids or bases are more commonly used.
Industrially, aspartate is frequently produced fromadmonition of fumaratecatalysed by L-aspartate ammonia lyase.
Racemic aspartic acid can be synthesized from diethyl sodium phthalimidomalonate(C6H4(CO)2NC(CO2Et)2).