Diamino acid
# Diamino acid

In chemistry, a diamino acid, also called a diamino carboxylic acid, is a molecule including a carboxylic acid and two amine functional groups. Diamino acids belong to the class of amino acids.

## Biochemical function

Lysine is a proteinaceous diamino acid (i.e. a component of proteins), and is accordingly coded by codons of the genetic material. In the pH range found inside living cells, both the amino groups are protonated, and they can be classified therefore as cationic amino acids.

Ornithine is a non-proteinaceous diamino acid.

In biochemistry, diamino acids are of particular interest. Diamino acids are used for the synthesis of specific peptide nucleic acids, such as daPNA. Artificial peptide nucleic acids are capable of forming duplex structures with individual DNA- and RNA-strands and are, therefore, not only called DNA-analog, but also they are considered as candidates for the first genetic material on Earth. The corresponding diamino acids such as 2,3-diaminopropanoic acid were detected in the Murchison meteorite and in a simulated comet.

## References and notes

* ↑ Egholm, M; Buchardt, O; Christensen, L; Behrens, C; Freier, SM; Driver, DA; Berg, RH; Kim, SK; Norden, B; Nielsen, PW (1993). "PNA hybridizes to complementary oligonucleotides obeying the Watson-Crick hydrogen bonding rules". Nature. 365 (6446): 566–568. Bibcode:1993Natur.365..566E. doi:10.1038/365566a0. PMID 7692304. S2CID 4318153.
* ↑ Meierhenrich, UJ; Munoz Caro, GM; Bredehöft, JH; Jessberger, EK; Thiemann, WHP (2004). "Identification of diamino acids in the Murchison meteorite". PNAS. 101 (25): 9182–9186. Bibcode:2004PNAS..101.9182M. doi:10.1073/pnas.0403043101. PMC 438950. PMID 15194825.
* ↑ Munoz Caro, GM; Meierhenrich, UJ; Schutte, WA; Barbier, B; Arcones Segovia, A; Rosenbauer, H; Thiemann, W; Brack, A; Greenberg, JM (2002). "Amino acids from ultraviolet irradiation of interstellar ice analogues". Nature. 416 (6879): 403–406. Bibcode:2002Natur.416..403M. doi:10.1038/416403a. PMID 11919624. S2CID 4391872.
