Meanwhile, amino acids are popular substances previously utilized in nanoparticle surface modification and as part of drug delivery systems . They are generally used for enhancing the stability of nanostructure properties due to their sustainable perspective which enables the promotion of additional chemical bonding with other substances via such functional groups (e.g., -NH2, etc.) . As amino acids have enriched functional groups and decent hydrophilic properties, they do not require organic solvents to be dissolved. Therefore, amino acids can serve as a core constituent material for organic-compound-based nanozyme (or organic nanozyme) as it fulfills the general requirements for constituent material of organic nanozyme. Additionally, amino acids are highly biocompatible (e.g., estimated by LD50 range), and denaturable in certain environments naturally, which contributes a higher sustainable characteristic when used in organic nanozymes . Among those amino acids, L-alanine is selected as a core organic material to form the nanozyme as it is a non-polar amino acid with a low molecular weight (89.09g/mol) and functional groups including an amine and a carboxylic acid group . The amine group in alanine enables the formation of a partially mimicked cofactor of natural peroxidase due to a chelation-driven coordinated bond with iron ion, residing the nanozyme's expected peroxidaselike activity. Additionally, OA nanozyme's surface charge can be unique depending on the buffering environments due to the existence of alanine and its isoelectric point which can be implemented for the barcode-like, charge-interaction based, target molecule binding strategies for further biomolecule-sensing-applications . Besides, identifying allergic biomolecules in agricultural, food, and biological environments is essential for preventing health issues. Histamine, one such biomolecule, is primarily stored in mast cells and basophils and can trigger allergic reactions. Higher concentrations of histamine beyond the acceptable level (e.g., normal range, <=10nMmL -1 ) (18) may cause allergy-like symptoms . Certain foods, including fermented foods, contain enriched histamine levels and may generate an allergic-like reaction which may hamper human health potentially . To monitor histamine concentration in agricultural, food, and biological substances, recent studies have proposed nanozyme-based sensing systems for effective detection . However, most of these systems using nanozymes are derived from inorganic nanozymes, which are not fully appropriate for direct implementation in agriculture and food environments. Additionally, most sensing systems require complicated strategies. Thus, a sustainable organic nanozyme-based, simplified histamine sensing system can overcome these limitations by offering sustainable and practical aspects. Furthermore, the surface-charge interaction-dependent histamine identification and detection provide high selectivity and enable the identification of histamine along with other biomolecules. This approach provides an easily accessible sensor system compared to the conventional antibody-antigen methodology while maintaining a reliable detection limit.