Site-directed alkylation and site-site interactions in bovine seminal ribonuclease

Active Site of Ribonuclease A

Ribonuclease A (RNase A; EC 3.1.27.5) was perhaps the most studied enzyme of the 20th century and is the best characterized ribonuclease. The “A” in its name refers not to its substrate specificity, but to the predominant form of the enzyme produced by the bovine pancreas. RNase A is unmodified, whereas RNase B, RNase C, and RNase D are mixtures of glycoforms. Because of its availability in lar...

Site-Directed Mutagenesis in Human Granulocyte-colony Stimulating Factor, Cloning and Expression in Escherichia coli

Human granulocyte colony stimulating factor (hG-CSF) induces proliferation and differentiation of granulocyte progenitor cells. This glycoprotein is currently being used for treatment of neutropenia, in patients who have undergone bone marrow transplantation. So far, different researchers have tried to enhance hG-CSF biological activity and stability. In this study, Polymerase Chain Reaction (P...

Site-directed ligand discovery.

We report a strategy (called "tethering") to discover low molecular weight ligands ( approximately 250 Da) that bind weakly to targeted sites on proteins through an intermediary disulfide tether. A native or engineered cysteine in a protein is allowed to react reversibly with a small library of disulfide-containing molecules ( approximately 1,200 compounds) at concentrations typically used in d...

Site-Directed Mutagenesis Study

Structural elements of the rat 1.t-opioid receptor important in ligand receptor binding and selectivity were examined using a site-directed mutagenesis approach. Five single amino acid mutations were made, three that altered conserved residues in the ~ 8, and K receptors (Asn 15°t Ala, His297 to Ala, and Tyr326 to Phe) and wo de igned to test for ~i/8 selectivity (lie198 to Val and Va1202 to li...

Site-Directed Covalent Immobilization