enzyme
It is an organic compound that acts as a catalyst for a biochemical reaction.They are the most efficient catalysts known, increase the rates of biochemical reactions by factors of up to 10^20 over uncatalyzed reactions.
in" and "yeast
The word enzyme comes from the Greek words en, which means _____ and zyme, which means ______.
simple enzyme
It is an enzyme composed only of protein (amino acid chains).
conjugated enzyme
It is an enzyme that has a nonprotein part in addition to a protein part.
cofactor
is the nonprotein part of a conjugated enzyme.
apoenzyme
It is the protein part of a conjugated enzyme.
holoenzyme
It is the bio- chemically active conjugated enzyme produced from an apoenzyme and a cofactor.
Apoenzyme + cofactor = holoenzyme
Formula for holoenzyme
coenzyme
It is a small organic molecule that serves as a cofactor in a conjugated enzyme.
substrate
It is the reactant in an enzyme-catalyzed reaction.
oxidoreductase
It is an enzyme that catalyzes an oxidation-reduction reaction.
dehydrogenase enzymes
It is an oxidoreductase that removes hydrogen atoms from a molecule.
transferase
It is an enzyme that catalyzes the transfer of a functional group from one molecule to another.
transaminases and kinases.
What are the two major subtypes of transferases?
transaminase
It catalyzes the transfer of an amino group from one molecule to another.
Kinases
It catalyze the transfer of a phosphate group from adenosine triphosphate (ATP) to give adenosine diphosphate (ADP) and a phosphorylated product (a product containing an additional phosphate group).
hydrolase
It is an enzyme that catalyzes a hydrolysis reaction in which the addition of a water molecule to a bond causes the bond to break.
Carbohydrases
They effect the breaking of glycosidic bonds in oligo- and polysaccharides
proteases
They effect the breaking of peptide linkages in proteins
lipases
They effect the breaking of ester linkages in triacylglycerols.
lyase
It is an enzyme that catalyzes the addition of a group to a double bond or the removal of a group to form a double bond in a manner that does not involve hydrolysis or oxidation.
dehydratase
They effects the removal of the components of water from a double bond
hydratase
They effects the addition of the components of water to a double bond.
isomerase
It is an enzyme that catalyzes the isomerization (rearrangement of atoms) of a substrate in a reaction, converting it into a molecule isomeric with itself.
oxidasesreductasesdehydrogenases
What are the three types of oxidoreductases?
oxidases
catalyzes the oxidation of a substrate
reductases
catalyzes the reduction of a substrate
dehydrogenases
catalyzes the introduction of double bond (oxidation) by formal removal of two H atoms from substrate, the H being accepted by a coenzyme
lipasesproteasesnucleasescarbohydrasesphosphatases
What are the five types of hydrolases
nucleases
catalyzes the hydrolysis of sugar-phosphate ester bonds in nucleic acids
phosphatases
catalyzes the hydrolysis of phosphate-ester bonds
dehydratasesdecarboxylasesdeaminaseshydratases
What are the four types of lyases
decarboxylases
removal of CO2 from substrate
deaminases
removal of NH3 from substrate
racemasesmutases
What are two types of isomerases
racemases
catalyzes the conversion of D to L isomer, or vice versa
mutases
catalyzes the transfer of a functional group from one position to another in the samemolecule
synthetasescarboxylases
What are the two types of ligases
synthetases
formation of new bond between two substrates, with participation of ATP
carboxylases
formation of new bond between a substrate and CO2, with participation of ATP
ligase
It is an enzyme that catalyzes the bonding together of two molecules into one with the participation of ATP.
active site
It is the relatively small part of an enzyme's structure that is actually involved in catalysis.
enzyme-substrate complex
It is the intermediate reaction species that is formed when a substrate binds to the active site of an enzyme.
Absolute Specificity
Such specificity means an enzyme will catalyze a particular reaction for only one substrate. This most restrictive of all specificities is not common. Urease is an enzyme with this.
Stereochemical Specificity
Such specificity means an enzyme can distinguish between stereoisomers. Chirality is inherent in an active site, because amino acids are chiral compounds. L-Amino-acid oxidase will catalyze reactions of L-amino acids but not of D-amino acids.
Group Specificity
Such specificity involves structurally similar compounds that have the same functional groups. Such as carboxypeptidase as it cleaves amino acids, one at a time, from the carboxyl end of the peptide chain.
Linkage Specificity
Such specificity involves a particular type of bond, irrespective of the structural features in the vicinity of the bond. Phosphatases hydrolyze phosphate-ester bonds in all types of phosphate esters. It is the most general of the specificities considered.
Enzyme activity
It is a measure of the rate at which an enzyme converts substrate to products in a biochemical reaction.
temperaturepHsubstrate concentrationenzyme concentration
What are the four factors affect enzyme activity:
Optimum temperature
It is the temperature at which an enzyme exhibits maximum activity.
extremozymes
Microbial enzymes that survive in such extreme environments are collectively called
Optimum pH
It is the pH at which an enzyme exhibits maximum activity.
turnover number
It is the number of substrate molecules transformed per minute by one molecule of enzyme under optimum conditions of temperature, pH, and saturation.
Concentration of Substrate
Reaction rate increases with substrate concentration until full saturation occurs; then the rate levels off.
Concentration of Enzyme
Reaction rate increases with increasing enzyme concentration, assuming enzyme concentration is much lower than that of substrate.
enzyme inhibitor
It is a substance that slows or stops the normal catalytic function of an enzyme by binding to it.
reversible competitive enzyme inhibitor
It is a molecule that sufficiently resembles an enzyme substrate in shape and charge distribution that it can compete with the substrate for occupancy of the enzyme's active site.
reversible noncompetitive enzyme inhibitor
It is a molecule that decreases enzyme activity by binding to a site on an enzyme other than the active site
irreversible enzyme inhibitor
It is a molecule that inactivates enzymes by forming a strong covalent bond to an amino acid side-chain group at the enzyme's active site.
allosteric enzyme
It is an enzyme with two or more protein chains (quaternary structure) and two kinds of binding sites (substrate and regulator).
regulators
Substances that bind at regulatory sites of allosteric enzymes are called _____.
other""site or space
The term allosteric comes from the Greek allo, which means _______ and stereos, which means ____.
Feedback control
It is a process in which activation or inhibition of the first reaction in a reaction sequence is controlled by a product of the reaction sequence.
allosteric control
It describes the process in which a regulatory molecule that binds at one site in an enzyme influences substrate binding at the active site in the enzyme.
proteolytic enzyme
It is an enzyme that catalyzes the breaking of peptide bonds that maintain the primary structure of a protein.
zymogen
It is the inactive precursor of a proteolytic enzyme.
Covalent modification
It is a process in which enzyme activity is altered by covalently modifying the structure of the enzyme through attachment of a chemical group to or removal of a chemical group from a particular amino acid within the enzyme's structure.
Glycogen phosphorylase
an enzyme involved in the breakdown of glycogen to glucose
Glycogen synthase
an enzyme involved in the synthesis of glycogen
antibiotic
It is a substance that kills bacteria or inhibits their growth.
Isoenzymes
are forms of the same enzyme with slightly different amino acid sequences.
Enzyme Active Site
a relatively small part of an enzyme's structure involved in catalysis
Enzyme-Substrate Complex
- intermediate formed when a substrate binds to the active site
Lock-and-Key Model
- The model of the enzyme that shows the substrate fitting perfectly into the active site- active site has a fixed, rigid geometrical conformation - only substrates with complementary geometry can fit on the active site
Induced-Fit Model
- Change in the shape of an enzyme's active site that enhances the fit between the active site and its substrate(s)- active site changes shape to accommodate a substrate
- can be used to diagnose certain diseases(appearance of certain enzymes in the blood)- can be used in the treatment of diseases(the use of tissue plasminogen activator (TPA))- clinical laboratory chemical analysis(test for the measurement of urea in the blood)
What are the uses of enzyme in medicine