Negative regulator of GDH1, the activator protein that regulates the ubiquitin ligase activity and substrate specificity of the anaphase promoting complex/cyclosome (APC/C), and which is required for exit from mitosis, cytokinesis and formation of prereplicative complexes in G1. Interacts with CDH1, BMH1 and BMH2. Expressed very quickly after G1 release, just prior to initiation of DNA replication. Present with 688 molecules/cell in log phase SD medium.