Substrate specificity of the human proteasome

Proteasome degradation: enter the substrate.

Cells depend upon the regulated destruction of their various proteins to maintain homeostasis and change their metabolic state. A key component of this process is the proteasome - a large multisubunit protease whose catalytic sites are sequestered within a central chamber. Entry of substrates into proteasomes is regulated by activators and is generally thought to proceed sequentially, starting ...

The structure and substrate specificity of human Cdk12/Cyclin K

Phosphorylation of the RNA polymerase II C-terminal domain (CTD) by cyclin-dependent kinases is important for productive transcription. Here we determine the crystal structure of Cdk12/CycK and analyse its requirements for substrate recognition. Active Cdk12/CycK is arranged in an open conformation similar to that of Cdk9/CycT but different from those of cell cycle kinases. Cdk12 contains a C-t...

The substrate specificity of fumarase.

The substrate specificity of fumarase has been studied by measuring the ability of the enzyme to hydrate or dehydrate derivatives of fumarate and L-malate. Fumarase was observed to hydrate fumarate and its derivatives in the order, fluorofumarate > fumarate > chlorofumarate > bromofumarate > acetylenedicarboxylate > iodofumarate > mesaconate. With the exception of fluorofumarate, water was adde...

The Role of Highly Conserved Tryptophan in the Sixth Conserved Region at Substrate Specificity of α- amylase

Early in this study, an α-Amylase from Bacillus megaterium WHO (BMW) was isolated from hot springs of Ramsar (North of Iran), and its gene was cloned in E.coli. Based on its conserved sequence regions and substrate specificity, it was classified as intermediary group enzymes with the specificity of oligo-1,6-glucosidase and neopullulanase subfamilies. In the sixth conserved re...

Substrate Specificity of MMPs