Exam 2: Lab 7 Digestive Enzymes Flashcards
What do enzymes do?
Proteins do work
How do enzymes and substrates in solutions find each other?
random molecular collison
how do enzymes and substrates interact?
enzymes + substrates E - S –> E + Product
- enzymes + substrates
- form and irriversibly form an enzyme substrate complex
- would irreversible regenerate the enzyme and create some product
What does it mean for an enzyme to be denatured
3-D shape has been changed
Do denatured enzymes work?
No. Function is highly dependent on its shape.
what can denature an enzyme
- high temperature
- pH
Each enzyme has a temperature and pH optimum. What does this mean?
- Function optimally in that range
- outside of range, it will not function optimally
Function of saliva
- to moisten food
- released by saliva: salivary amylase enzyme
starch
- amylose
- enzyme break it down is amylase
in order to absorb food from small intestine to blood
- must break it all the way down into its monomer subunit
- if not shit it out
once food is swallowed:
pharynx to esophagus to stomach to small intestine to duodenum
mouth has pH of?
stomach has pH of?
- mouth: rough pH of 7 (neutral)
- stomach: rough pH of 2 (acidic)
amylase
- enzyme works well with pH of 7 (neutral)
- gets denatured in stomach pH 2 acidic
- gets released in small intestine by duodenum in pancreatic juice called pancreatic amylase
function of stomach
- temporary storage of food
- no enzymes to breakdown sugar, fat,
enzyme in stomach
- pepsin
pepsin
- activated with low pH
- take big protein and it make it small protein, but not break all the way down to individual amino acids
small intestines
- key to digestive system
- where vast majority of digestion and absorption occurs
- duodenum: 5% of s.i pancreatic juices released
pancreatic juice
- enzymes
- all the enzymes that breakdown food stuff are in juice (pancreatic duct); including pancreatic amylase
breakdown digestion:
- all the lipase (fat) and all the protease (protein) released into small intestine get digestion
- break down all other carbohydrates released in duodenum
IKI result
- K iodine
- results for breakdown of starch (amylose)
- black original
- if positive breakdown: goes lighter
- if negative/no breakdown: black
Benedict’s result for starch breakdown
- look for maltose
- orange positive = there was breakdown of starch
- light blue = no breakdown of starch
5 ml amylose + 5 drops amylase (enzyme)
IKI:
Benedicts:
- IKI = dark brown to copper (positive for IKI/all starch broke down) in 6 min
- Benedict’s result = orange/maltose seen/breakdown of starch +)
5 ml amylose + 1 drop HCl + 5 drops of amylase
IKI:
Benedicts:
- IKI = Black, no change, no breakdown of starch seen, HCl denatured enzyme
- Benedict’s = negative, no maltose seen, HCl denatured enzyme, no digestion occured
5 ml amylose + 2 drop amylase
- IKI = dark purple to copper in 8 min; positive for breakdown; slower due to lower concentration of enzyme
- Benedict’s: positive complete breakdown but slower; saw maltose present
5 ml amylose + 5 drop boiled amylase
- IKI = no breakdown, black all the way; temperature denatured enzyme
- Benedict’s = no breakdown, no maltose seen; no digestion occurred due to denatured enzyme
5 ml cold amylase + 5 drop cold amylase
then after room temp
- IKI no break down occurred: all black due to cold slows enzymes down but doesn’t break it down
- after room temp:
1. IKI = all sugar broken down; copper all the way
2. Benedict’s = positive, saw maltose; cold slow enzyme down.
Protein digestion experiment: with egg
- positive result
- 37 C = room temp
- 1 drop HCl
- 5 ml pepsin
- HCl (low pH) activates pepsin to break down protein in room temperature otherwise any changes from that, no breakdown occurs.
- if temp change 0 C
- if no enzymes (H20)
- if base added Na+OH
- If no HCl added (H20)
