Catalase is one of the most efficient enzymes known, breaking down hydrogen peroxide into water and oxygen at rates of up to 40 million reactions per second. In this investigation, you will measure how the rate of catalase activity changes as substrate concentration increases, generating a Michaelis-Menten curve and allowing calculation of the maximum reaction velocity (Vₘₐˣ) and the Michaelis constant (Kₘ). This is a fully quantitative IB Biology HL Internal Assessment investigation. This practical is suitable for IB Diploma Biology HL and Edexcel IGCSE Biology.