<prompt> Hormone substrate concentration affects the velocity of enzymatic action. This is based upon the following:Zimmermann reactionSalkowski reactionMichaelis menten equationLiebermann-Burchard reaction  <response>: The Michaelis-Menten equation illustrates in mathematical terms the relationship between initial reaction velocity vi and substrate concentration . ViVmax Km The Michaelis constant Km is the substrate concentration at which vi is half the maximal velocity Vmax2 attainable at a paicular concentration of the enzyme. Ref: Kennelly P.J., Rodwell V.W. 2011. Chapter 8. Enzymes: Kinetics. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell Eds, Harpers Illustrated Biochemistry, 29e. 