In prokaryotic organisms, protein complexes are essential for optimizing metabolic pathways and enabling adaptation to dynamic environmental conditions. This chapter would emphasize into the classification and functional characterization of these complexes, as revealed by large-scale screening studies. Central to prokaryotic metabolism, key complexes involved in carbohydrate, amino acid, fatty acid, and nucleotide metabolism are organized in a factory-like manner to maximize efficiency. Regulatory mechanisms, including allosteric regulation, transcriptional control, and post-translational modifications, play a critical role in modulating the activity of these complexes in response to metabolic needs and environmental fluctuations. Notably, proteins such as trigger enzymes exhibit condition-specific adaptations, enabling swift responses to changing nutrient levels and supporting bacterial pathogens in their intracellular survival strategies. The chapter also examines the relationship between protein half-life, expression patterns, and metabolic fluxes. Under optimal growth conditions, a strong correlation emerges between metabolite flow through carbohydrate pathways and the regulation of gene expression. Furthermore, the ecological implications of prokaryotic metabolic adaptability are explored, highlighting its role in nutrient cycling and symbiotic interactions. By uncovering the intricate regulatory networks governing prokaryotic metabolism, this review underscores their importance in survival under extreme conditions and their potential applications in biotechnology and environmental remediation. Synthesizing recent research, the chapter aims to illuminate the core principles of metabolic regulation in prokaryotes, providing valuable insights for advancing microbial ecology, synthetic biology, and metabolic engineering.