Science Snippet: Examining Enzymes

Structure of a pyruvate kinase, an enzyme that adds a phosphate group to adenosine diphosphate (ADP) to make adenosine triphosphate (ATP). Credit: PDB 7UEH. Every day, our cells must produce all the various molecules they need to stay alive. But the chemical reactions to create these molecules can’t occur without help—which is where enzymes come in. Enzymes are biological catalysts, meaning they speed up the rate of specific chemical reactions by reducing the amount of energy needed for the reaction to occur. Most enzymes are proteins, but some RNA molecules can also act as enzymes. Thousands of different enzymes catalyze the vast range of reactions that take place within cells, but each enzyme typically supports one of the following types of tasks: Joining two molecules together by making a new chemical bond Breaking down a molecule into two or more new molecules by splitting a chemical bond Adding or removing specific groups of atoms, called functional groups, to or from a molecule Changing the overall shape of a molecule without adding or removing atoms For example, kinases are enzymes that add phosphate groups (a phosphorous atom bonded to four oxygen atoms) to molecules. Conversely, phosphatases are a type of enzyme that removes phosphate groups from molecules. The addition and subtraction of phosphate groups can activate or deactivate a signaling molecule or even a protein. Cells’ major source of energy, adenosine triphosphate (ATP), is a...
Source: Biomedical Beat Blog - National Institute of General Medical Sciences - Category: Research Authors: Tags: Cells Chemistry, Biochemistry and Pharmacology Cellular Processes Proteins Science Snippet Source Type: blogs