HOOCCHOH4COOH

HOOCCHOH4COOH is not a standard common or IUPAC name for a single well-defined compound. As written, it resembles a condensed or informal representation of a four‑carbon hydroxy diacid, but the exact connectivity is ambiguous without explicit structural notation. A widely known molecule that fits a four‑carbon hydroxy diacid pattern is malic acid, which has the structure HOOC-CHOH-CH2-COOH.

Malic acid is an alpha-hydroxy dicarboxylic acid and a natural metabolite in many fruits. It contains one stereogenic carbon and exists as two enantiomers, L- and D-malate, with L-malate being the biologically predominant form in metabolism. In biochemistry, malate is an intermediate in the citric acid cycle, converting to oxaloacetate via malate dehydrogenase and contributing to cellular energy production. In aqueous solution, malic acid behaves as a diprotic acid, with the two carboxyl groups contributing to acidity; at physiological pH it is largely present as the dianion.

In practical terms, malic acid is used as a food acidity regulator (often labeled as E296) and as a flavor enhancer or buffering agent. It also appears in cosmetic formulations and serves as a seed to synthesize other intermediates in organic and biochemical research. While other isomers of hydroxy dicarboxylic acids exist (such as tartronic or tartaric acids), HOOCCHOH4COOH does not correspond to a single universally recognized compound without explicit structural detail.

See also: malic acid, tartronic acid, tartaric acid, citric acid.