User:BillNye08/Peptidyl-dipeptidase Dcp

Introduction
Peptidyl-dipeptidase Dcp (, dipeptidyl carboxypeptidase (Dcp), dipeptidyl carboxypeptidase) is a metalloenzyme found in in the cytoplasm of bacterium E. Coli responsible for the C-terminal cleavage of a variety of dipeptides and unprotected larger peptide chains. The enzyme does not hydrolyze bonds in which P1' is Proline, or both P1 and P1' are Glycine. Dcp is comprised of 680 amino acid residues which organize into monomers to aid in the intracellular degradation of peptides. Metallic divalent cations inhibit the function of the enzyme Dcp which coordinated to divalent zinc which sits in the pocket of the active site, and is composed of four subsites: S1’, S1, S2, and S3 Basic amino acids accumulate at the S1 site, The S2 site sits deeper into the enzyme and has limited access to hydrophobic amino acids. Since amino acids prefer to be located at certain regions of the enzyme, it enhances the selectivity and proves the enzyme has high specificity for certain properties of amino acids. A pair of histidine residues bind to the catalytic zinc ion in similar fashion as reported by Menach et al. The enzyme is vertically elongated and has a deeper inner cavity where the active site is and is divided into two subdomains (I, and II). Peptidyl-Dipeptidase Dcp is classified like oligopeptidase A and Angiotensin-I converting enzyme (ACE) due to structural comparability but must be examined separately based on their discrepancy of peptidase activity. ACE has endopeptidase activity, whereas Dcp strictly has exopeptidase activity based on its cytoplasmic location and therefore their mechanisms of action are differentiated. Another difference between these enzymes is that the activity of Peptidyl-Dipeptidase Dcp is not enhanced in the presence of chloride anions, which is not the case for ACE.

Introduction
Peptidyl-dipeptidase Dcp (, dipeptidyl carboxypeptidase (Dcp), dipeptidyl carboxypeptidase) is a metalloenzyme found in in the cytoplasm of bacterium E. Coli responsible for the C-terminal cleavage of a variety of dipeptides and unprotected larger peptide chains. The enzyme does not hydrolyze bonds in which P1' is Proline, or both P1 and P1' are Glycine. Dcp is comprised of 680 amino acid residues that form into a single active monomer which aids in the intracellular degradation of peptides. Dcp coordinates to divalent zinc which sits in the pocket of the active site and is composed of four subsites : S1’, S1, S2, and S3, each subsite attracts certain amino acids at a specific position on the substrate enhancing the selectivity of the enzyme. The four subsites detect and bind different amino acid types on the substrate peptide in the P1 and P2 positions. Some metallic divalent cations such as Ni+2, Cu+2, and Zn+2 inhibit the function of the enzyme around 90%, whereas other cations such as Mn+2, Ca+2, Mg+2, and Co+2 have slight catalyzing properties, and increase the function by around 20%. Basic amino acids such as Arginine bind preferably at the S1 site, the S2 site sits deeper in the enzyme therefore is restricted to bind hydrophobic amino acids with phenylalanine in the P2 position. Dcp is divided into two subdomains (I, and II), which are the two sides of the clam shell-like structure and has a deep inner cavity where a pair of histidine residues bind to the catalytic zinc ion in the active site. Peptidyl-Dipeptidase Dcp is classified like Angiotensin-I converting enzyme (ACE) which is also a carboxypeptidase involved in blood pressure regulation, but due to structural differences and peptidase activity between these two enzymes they had to be examined separately. ACE has endopeptidase activity, whereas Dcp strictly has exopeptidase activity based on its cytoplasmic location and therefore their mechanisms of action are differentiated. Another difference between these enzymes is that the activity of Peptidyl-Dipeptidase Dcp is not enhanced in the presence of chloride anions, whereas chloride enhances ACE activity.