Adenine

(A, Ade) is a nucleobase associated with biochemistry. As a purine derivative, it has several essential roles in biological processes. This article explores the structure, synthesis, function, and history of adenine.

Overview

Adenine is an integral part of cellular respiration, specifically in the formation of the energy-rich molecule adenosine triphosphate (ATP). Moreover, it acts as a constituent of the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD). Furthermore, it is pivotal in protein synthesis, being a primary component of both DNA and RNA. In DNA, adenine pairs with thymine, whereas in RNA, it complements uracil.

Structure

Error creating thumbnail:

Numbered structure of adenine.

Several tautomers of adenine exist, which can rapidly interconvert, leading them often to be treated as equivalent. Notably, under specific isolated conditions, such as in an inert gas matrix or in the gas phase, the 9H-adenine tautomer predominantly exists.

Biosynthesis

The metabolic pathway of Purine metabolism oversees the formation of both adenine and guanine. These nucleobases trace back to the nucleotide inosine monophosphate (IMP). This nucleotide is synthesized on a pre-existing ribose phosphate backbone. The pathway incorporates atoms from amino acids like glycine, glutamine, and aspartic acid, and it also fuses with the enzyme tetrahydrofolate.

Function

Among the purine nucleobases, adenine and guanine are crucial for constructing the nucleic acids. In DNA structures, adenine's role is to bind with thymine through two hydrogen bonds, ensuring stability. For protein synthesis in RNA, adenine pairs with uracil.

File:Base pair AT.svg File:Base pair AU.svg File:Base pair APsi.svg

Pairs: A-T (DNA) | A-U (RNA) | A-D (RNA) | A-Ψ (RNA)

When attached to ribose, adenine forms the nucleoside known as adenosine. When linked to deoxyribose, it produces deoxyadenosine. The addition of three phosphate groups to adenosine results in the formation of adenosine triphosphate (ATP). This nucleotide is vital in cellular metabolism, facilitating energy transfer between chemical reactions.

History

Historically, adenine was referred to as Vitamin B₄ in older scientific literature. Although it is no longer classified as a true vitamin or part of the Vitamin B complex, it does associate with the B vitamins, niacin and riboflavin. These vitamins combine with adenine to create essential cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD).

Adenine was named by Albrecht Kossel in 1885, inspired by the pancreas (in Greek, "aden") from which his sample was derived. Experiments in 1961 revealed that adenine could be synthesized from the polymerization of ammonia with five hydrogen cyanide molecules. The implications of these findings on the origin of life on Earth are still debated.

In 2011, studies on meteorites suggested that adenine might have extraterrestrial origins, indicating that the building blocks of DNA and RNA could form in outer space.

External links

• Vitamin B4 MS Spectrum

Vitamins A Vitamin A B Biotin Vitamin B1 (see Thiamin) Vitamin B12 Vitamin B6 C Calcium Choline Chromium Copper Vitamin C D Vitamin D

E Energy Drinks Exercise and Athletic Performance Vitamin E F Fluoride Folate I Iodine Iron K Vitamin K

M Magnesium Multivitamin/mineral Supplements N Niacin P Pantothenic Acid Phosphorus Potassium Primary Mitochondrial Disorders R Riboflavin

S Selenium T Thiamin V Vitamin A Vitamin B1 (see Thiamin) Vitamin B12 Vitamin B6 Vitamin C Vitamin D Vitamin E Vitamin K Z Zinc