Non-protein compounds called co-factors are required for some proteins in order to facilitate enzymatic activity. Common examples of co-factors are metal ions (Ca2+, Mg2+ etc.), organic co-factors such as heme (in hemoglobin), among others.
phospholipid and cholesterol
Enzymes are proteins that catalyze (i.e., increase the rates of) chemical reactions.[1][2] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. Almost all processes in a biological cell need enzymes to occur at significant rates. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.Like all catalysts, enzymes work by lowering the activation energy (Ea‡) for a reaction, thus dramatically increasing the rate of the reaction. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts by being much more specific. Enzymes are known to catalyze about 4,000 biochemical reactions.[3] A few RNA molecules called ribozymes also catalyze reactions, with an important example being some parts of the ribosome.[4][5] Synthetic molecules called artificial enzymes also display enzyme-like catalysis.[6]Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity; activators are molecules that increase activity. Many drugs and poisons are enzyme inhibitors. Activity is also affected by temperature, chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or fat stains on clothes; enzymes in meat tenderizers break down proteins, making the meat easier to chew).
Transport vesicles play a key part in moving molecules to and from the membrane-confined chambers of the secretory pathway. Proteins are transported in vesicles; the proteins are made on the cytosolic side of membranes.
The part of the enzyme where the substrate attaches itself to is known as the "active site". The active site of an enzyme is a part of the molecule that has just the right shape and functional groups to bind to one of the reacting molecules. The reacting molecule that binds to the enzyme is called the substrate.
Temperature affects enzyme activity by altering the rate of reaction. Increasing temperature generally speeds up enzyme activity, as molecules move faster and collide more frequently. However, extremely high temperatures can denature the enzyme, disrupting its shape and reducing its activity.
Proteins are part of the 4 main organic molecules, Carbohydrates, nucleic acids, lipids, and proteins. They are carbon based molecules that have an amino and carboxyl group.
These are the proteins.
Reaction equilibrium
Complement proteins signaling phagocytes
Globular proteins.
The salivary glands have an enzyme called amylase that begins the breakdown of starch.
phospholipid and cholesterol
Globular proteins
The great majority of enzymes are proteins.Proteins are well suited to the job of catalysis, as they can fold into specific three-dimensional shapes that complement the shapes of their substrates.A few enzymes are RNA. For example, the activity of ribosomes depends in part on the catalytic activity of ribosomal RNA (rRNA).
Enzymes are proteins that catalyze (i.e., increase the rates of) chemical reactions.[1][2] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. Almost all processes in a biological cell need enzymes to occur at significant rates. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.Like all catalysts, enzymes work by lowering the activation energy (Ea‡) for a reaction, thus dramatically increasing the rate of the reaction. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts by being much more specific. Enzymes are known to catalyze about 4,000 biochemical reactions.[3] A few RNA molecules called ribozymes also catalyze reactions, with an important example being some parts of the ribosome.[4][5] Synthetic molecules called artificial enzymes also display enzyme-like catalysis.[6]Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity; activators are molecules that increase activity. Many drugs and poisons are enzyme inhibitors. Activity is also affected by temperature, chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or fat stains on clothes; enzymes in meat tenderizers break down proteins, making the meat easier to chew).
Globular proteins
Complement proteins are molecules, not cells. They are part of the innate immune system and function to enhance the ability of antibodies and phagocytic cells to clear pathogens from the body.