How are opposing anabolic and catabolic pathways with shares reactions regulated? what type of enzymes in such reactions serve as the point of regulation?

Catabolic reactions are those that breakdown the complex molecules into simpler one and generate energy. While Anabolic reactions are those that utilize energy to for the synthesis of complex molecules from smaller molecules.  

Both the pathways are regulated by separate enzymes. Enzymes with ΔG equal to zero, that is nearly equilibrium condition, are used to regulate these pathways. Both pathways are regulated differentiately to ensure the proper functioning and maintain balance.