6. Enzymes 1 Flashcards
who created the lock and key hypothesis
emil fischer
what did Louis Pasteur find
fermentation requires living cells
who proposed the term enzyme
Wilhelm kühne
what are 3 functions of biological catalysts
1) regulate the flow of molecules through all metabolic pathways
2) build structures of cells
3) break down invading pathogens (lysozyme)
name 3 uses of biological catalysts in every day life
1) washing detergents - proteases, lipases
2) cotton textile- cellulase, de-starching amylase
3) fondant centres, invertase prevents crystallisation (e..g in a creme egg)
give an example of an enzyme with low specificity
subtilisin - bacterial protease, cleaves bonds indiscriminately
give an example of an enzyme with moderate specificity
trypsin - a digestive enzyme that cleaves peptide bonds
give an example of an enzyme with high specificity
thrombin- blood clotting enzyme, cleaves between Arg and Gly in specific motifs
what do most proteolytic enzymes end in
“-in”
e.g. trypsin, pepsin
what does EC mean
enzyme commission number
what is the purpose of EC numbers
an enzyme classification system, takes the form “1,2,3,4”
what do each of the four numbers in EC numbers represent
1= broad class of enzyme 2 & 3= details of reaction, e.g. bonds 4= substrate
what are the three measures of enzyme activity
rate of reaction
SI unit (Katal)
International activity unit (U)
what does SI unit mean
amount of enzyme that converts 1 mol of substrate per second
what does international
activity unit mean
amount of enzyme that will catalyse the transformation of 1 micromole of substrate per minute
what is an exergonic reaction
occur spontaneously and release energy to surroundings
what is an endogonic reaction
require input of energy
what is the initial ‘spark’ of energy required to activate a reaction called
activation energy of Gibbs free energy of activation
what is the definition of free energy
energy in a system that can be converted to perform work. essentially the amount of energy tied up in the bonds of molecules
what is the transition state
at the summit of the reaction where molecules are unstable
what is △G
total reaction change in free energy
true or false:
enzymes work by altering △G
false: they do not change △G , they work by hastening reaction that would eventually occur
