Ismatul Nurul Asyikin IsmailHanina Mohd NoorHairul Shahril MuhamadSalina Mat RadziAbdul Jalil Abdul KaderMaryam Mohamed RehanRosfarizan Mohamad2024-05-272024-05-2720131/9/2020American Journal of Biological, Chemical and Pharmaceutical Sciences Vol. 1, No. 6, October 2013, PP: 35 - 41, ISSN: 2328 - 6814 (Online) Available online at http://www.ajbcps.com/2328-68142387-4http://www.ajbcps.com/Vol.%201,%20No.%206,%20October%202013.phphttps://oarep.usim.edu.my/handle/123456789/3664Many studies have reported that the primary activity of most inhibitors of bacterial function is to modulate transcription processes at much lower concentrations than that required for antibiosis. Therefore, the bacteria might be produced and secreted more proteins in the mild stress surroundings (e.g. in the presence of low doses of antimicrobial agents) than in the normal environment. However, not much is known about unexpected ability of natural antimicrobial compounds at low concentration to become a signaling agent that capable to modulate biological functions in bacteria. Thus, this study aims to explore the potential of natural antimicrobial compound (Allium sativum) at sub-minimal inhibitory concentration (sub-MIC) in regulating proteins production by Bacillus subtilis ATCC 21332. The Minimum Inhibition Concentration (MIC) of A. sativum on B. subtilis resulting 14.29% was determined by microdilution assay. The bacteria cells were further exposed to A. sativum at sub-MIC (0.05 x MIC) in fermentation process. SDS-PAGE profile showed that two protein bands with approximate size of 51.36 kD and 9.74 kD were produced for the bacteria treated with A. sativum. LC-MS/MS analysis identified six possible proteins from the two bands expressed in mild stress condition. The proteins exhibited antimicrobial activity towards several Gram-positive and Gram-negative bacteria. Hence, B. subtilis ATCC 21332 in mild stress condition with the presence of 0.05 x MIC A. sativum could regulate bioactive proteins production. Copyright © AJBCPS, all rights reserved. Keywords: Bacillus subtilis ATCC 21332, Allium sativum, proteins, sub-MIC, antimicrobial agent, transcriptionenBacillus subtilis ATCC 21332,Allium sativum,proteins,sub-MIC,antimicrobial agent,transcriptionArticle354116