Enzymes Flashcards
Enzymes
proteins that act as biological catalysts
decrease delta G to facilitate reaction
normally inside the cells; only in blood when cells are damaged
Enzyme reaction factors
time substrate level pH of mixture temperature enzyme concentration activators/inhibitors that may be present
Time
fixed or kinetic (series of times)
product formation different depending on the time
substrate
goal is to make so much substrate available so that it does not become a limiting factor & makes all the reactions a zero order reaction time
pH of mixture
most rx use pH of 7-8
temperature
optimume 37 in US; 30 in europe
enzyme concentration
originate from patient samples
activators/inhibitors
activators aid enzyme reaction to be optimum
inhibitors compete & reaction is not optimum (drugs in patient’s system etc)
Inhibitors
competitive- binds to enzyme active site
uncompetitive- binds to ES complex
non-competitive - binds to other site & causes conformational change
reversible : can ‘dilute’ off
non reversible : alters active site permanently
International Unit (IU)
the amount of enzyme which can convert 1 umol of substrate per minute to product
Systemic Unit (SI)
katal unit - amount of enzyme that catalyzes 1 mole of substrate per second
Isoenzymes
forms of an enzyme that are molecularly different but catalyze the same reaction
can usually be separated by electrophoresis or Ab-Ag reaction
Creatine Kinase
associated with ATP regeneration in muscle & transport systems
found in heart, muscle, & brain tissue
elevated CK associated with AMI, muscular dystrophy, CNS seizures etc etc etc
Zero-order kinetics
substrate > enzyme
reaction rate proportional to enzyme
Active Site
site where substrates attached and undergo chemical reaction
