Epitalon (Epithalon, AEDG) vs NAD+ (Nicotinamide Adenine Dinucleotide)

Epitalon (Epithalon, AEDG)

Epitalon, also spelled epithalon, is the synthetic tetrapeptide Ala-Glu-Asp-Gly, modelled on epithalamin, a peptide extract of bovine pineal gland. It came out of a Russian research programme on short regulatory peptides, and nearly all of the published work comes from that programme and its collaborators. The studies include cultured human cells, rodents and fruit flies, together with some human studies reported mostly in Russian-language journals. The topics are ageing biology, telomere maintenance and pineal function. Independent replication outside that group is limited, and the human data are sparse and come almost entirely from the same source.

NAD+ (Nicotinamide Adenine Dinucleotide)

NAD+, nicotinamide adenine dinucleotide, is a non-peptide coenzyme formed from two nucleotides joined through their phosphate groups. One nucleotide carries adenine and the other nicotinamide, a form of vitamin B3, and the molecule occurs in every living cell. Cells can make it from tryptophan or nicotinic acid, but mammalian cells rely mostly on a salvage pathway that recycles nicotinamide, with the enzyme NAMPT setting its pace. Identified in yeast extracts more than a century ago, it has long been central to enzymology; recent work, mostly in rodents and cell culture, concerns its roles in signalling and how its levels change with age and metabolic state. Human data on exogenous NAD+ remain limited.

How Epitalon (Epithalon, AEDG) acts

No receptor for Epitalon has been identified, and most mechanistic proposals come from the same research school. Cell-culture studies from that group have reported induction of telomerase activity and telomere elongation in human somatic cells, which normally express little telomerase. Other papers propose that short peptides of this kind enter the nucleus and bind DNA or histones, altering the expression of particular genes; this idea has not been widely tested elsewhere. Animal studies have examined melatonin secretion by the pineal gland and circadian markers. The overall picture rests on a narrow base of laboratories.

How NAD+ (Nicotinamide Adenine Dinucleotide) acts

NAD+ accepts a hydride ion to become NADH, and the NAD+/NADH pair carries electrons from glycolysis and mitochondrial dehydrogenases to complex I of the respiratory chain. Beyond this redox role, three enzyme families consume NAD+ as a substrate: the sirtuins, which remove acetyl and other acyl groups from proteins; the poly(ADP-ribose) polymerases (PARPs), which are activated by DNA strand breaks; and CD38 and related enzymes, which generate signalling molecules such as cyclic ADP-ribose. NAD+ outside cells is generally thought to be broken down by cell-surface enzymes into smaller precursors before cells take it up, so the fate of exogenous NAD+ is itself a research question.

The records side by side

• Type: Epitalon (Epithalon, AEDG), Tetrapeptide; NAD+ (Nicotinamide Adenine Dinucleotide), Coenzyme (dinucleotide)
• Length: Epitalon (Epithalon, AEDG), 4 amino acids; NAD+ (Nicotinamide Adenine Dinucleotide), not recorded
• Molecular weight: Epitalon (Epithalon, AEDG), 390.35 g/mol; NAD+ (Nicotinamide Adenine Dinucleotide), 663.4 g/mol
• Molecular formula: Epitalon (Epithalon, AEDG), C14H22N4O9; NAD+ (Nicotinamide Adenine Dinucleotide), C21H27N7O14P2

Reading a comparison

A comparison places two records side by side; it does not merge them. Each description above is drawn from that compound's own record, and the two were not necessarily characterised by the same methods, at the same time, or to the same level of detail. Before comparing any attribute, it is worth establishing that both records describe the substance you think they describe — names are not identifiers, and two entries sharing a name can differ in salt form, stereochemistry or the convention used to state a mass. Where a figure carries no method beside it, the comparison is between two reported numbers rather than between two measurements.