Function as an enzyme

All organisms seem to have an absolute need for magnesium. In plants, the magnesium complex chlorophyll is the prime agent in photosynthesis. In animals, magnesium functions as an enzyme activator the enzyme which catalyses the ATP hydrolysis mentioned above is an important example. 

Proteins start out life as a bunch of amino acids linked together in a head-to-tail fashion—the primary sequence. The one-dimensional information contained in the primary amino acid sequence of cellular proteins is enough to guide a protein into its three-dimensional structure, to determine its specificity for interaction with other molecules, to determine its ability to function as an enzyme, and to set its stability and lifetime. 

Pharmacology Calcium is essential for the functional integrity of the nervous and muscular systems, for normal cardiac contractility and the coagulation of blood. It also functions as an enzyme cofactor and affects the secretory activity of endocrine and exocrine glands. 

Many biological molecules, such as proteins, are large and have complex structures. Proteins are composed of a sequence of units, called amino acids, which are joined by a strong covalent bond known as a peptide bond. But proteins also fold up into a certain shape, which is vital to their function—a protein that loses its shape cannot fulfill its function as an enzyme or a transporter. The sequence of amino acids determines the shape 20 different amino acids are found in proteins, and each one has slightly different chemical and physical properties. For example, some amino acids are hydrophilic, readily interacting... 

The prepolymer used for this study was an MDI-based preparation (Suprasec 1002) from Huntsman PU, Brussels, Belgium. Immobilization of the enzyme was accomplished by coating the inside structure of a reticulated foam with an acetone solution of a hydrophilic polyurethane prepolymer. A 45-pore/in. reticulated foam cut into sheets 0.25 in. thick was used. The coated reticulated foam was immersed in a catalase solution (5 pg/ml) at 4°C and left in the solution for 1 hour to ensure a complete solution. It is known that both the water and some functionality in the catalase react with the isocyanate groups to cause polymerization (the water-isocyanate reaction) and chain termination (the catalase reaction). Controlling the relative concentrations and temperature permits control of the physical properties of the composite and the ability of the foam to function as an enzyme. 

Calcium, in contrast to magnesium, does not have an important function as an enzyme activator, in accord with its different distribution. It is very important, however, in the control and triggering of biological processes such as muscle contraction and the release of various chemicals, including hormones, defence chemicals and neurotransmitters. This occurs when, in response to some stimulus, the normal selectivity of the cell membrane or the membranes of internal organelles breaks down, and calcium ions are allowed to enter the cell. These bind to specific sites and trigger certain reactions. 

In summary, a pore may function as an enzyme, with transport enhanced ( catalyzed ) in two ways ... 

Manganese is an essential trace element and functions as an enzyme activator in cellular respiration. Specifically,... 

The hypothesis that nickel in animals may function as an enzyme cofactor has been stimulated by the discovery that urease from several plants and microorganisms is a nickel metalloenzyrne (20-25). Dixon al. (20) found that highly purified urease (E.C.3.5.1.5) from jack beans (Canavalia enslformls) contained stoichiometric amounts of nickel,... 

Superoxide dismutase (SOD) was discovered in the 1960s by McCord and Fridovich in bovine erythrocytes where they described its functions as an enzyme which catalyzes the dismutation of superoxide radicals (Oj + O2 + 2H 02 + HjOj) (McCord and Fridovich 1969). Since the discovery of SOD, there are four isofoims of the enzyme which have been identified and they include Ni-SOD (cytoplasmic), Mn-SOD (mitochondrial), Cu/Zn-SOD (cytoplasmic), and EC-SOD (extracellular) (Mates and Sanchez-Jimenez 1999). The product of the dismutation of two superoxide anions carried out by SOD is the ROS, hydrogen peroxide, therefore biologically this enzyme is often coupled with antioxidants that remove hydrogen peroxide such as catalase and glutathione peroxidase. 

A remarkable form of RNA is the ribozyme, a single-strand structure with the capadty— highly improbable as it appeared when first discovered— to catalyse the fracture of its own chain or that of other RNAs. That something so restricted in its structural possibilities as a nucleic add could function as an enzyme... 

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