Hello all! I am studying for a Biochem exam and am having issues understanding how Koshland's Sequential model accounts for negative homotropic effectors. (aka, substrate binds and next substrate is less likely to bind leading to a higher cooperativity) If someone could please give me some sort of a link to a diagram or simply explain it to me that would be great! Google search is not working to well.

You might try searching on negative cooperatively. In the book Structure and mechanism in protein science, Alan Fersht has a very brief treatment on pages 296-297 (second edition).