- WELCOME TO PROTEINS AND ENZYMES PART 10.
IN THIS TUTORIAL, WE ARE GOING TO LOOK
AT ENZYME CLASSIFICATIONS AND BEGIN RECOGNIZING
THE TYPES OF REACTIONS EACH DIFFERENT CLASSIFICATION
WILL CATALYZE.
LET'S GET STARTED. ALL RIGHT.
SO, WE'RE GOING TO FOCUS ON SIX MAIN CLASSES OF ENZYMES,
YOU KNOW, THERE'S ALWAYS MORE WHEN PEOPLE GET INTO DETAILS,
BUT THIS IS THE HEART OF THE MATTER.
SO IN OUR STUDY OF FUNCTIONAL GROUP REACTIONS,
WE SEE THAT OXIDATION AND REDUCTION ARE VERY IMPORTANT,
SO THERE'S NO SURPRISE HERE. THE OXIDOREDUCTASE ENZYMES
WILL BE EASY TO SPOT BECAUSE YOU'LL RECOGNIZE AN OXIDATION
AND REDUCTION REACTION AND THEY HAVE A HUGE FLAG.
BECAUSE IT'S REDOX...
SO, THEY REQUIRE A COENZYME.
SO, THERE'S ALWAYS A VERY OBVIOUS FLAG
FOR THE OXIDOREDUCTASE ENZYMES.
WE'LL SEE NAD+ WITH NADH, OR FAD WITH FADH2,
OR NADPH WITH NADP.
LOOK FOR THOSE COENZYMES, THE BIG HUGE FLAG.
WE'LL ALSO SEE THAT TRANSFERRING FUNCTIONAL GROUPS.
SO VERY FREQUENTLY.
WE WILL SEE THE PHOSPHATE GROUP TRANSFERRED
AND OFTEN SYMBOLIZED WITH LIKE A P1 OR A PI.
ACYL GROUPS ALSO VERY FREQUENTLY TRANSFERRED OR AMINES.
OFTEN, YOU WILL SEE KINASE AND THE ENZYME NAME.
AND SO AS I MENTIONED THESE FUNCTIONAL GROUPS,
IDEALLY IN YOUR MIND YOU SEE THEM.
SO WE THINK ABOUT A PHOSPHATE GROUP GETTING TRANSFERRED
AND IT JUST BE STRAIGHTAWAY LIKE THAT.
ACYL GROUPS, RIGHT, THINK ABOUT THAT CARBONYL.
HERE WILL BE THE ACYL GROUP.
OR AMINES.
NOW HAVE--WATER WILL SHOW UP IN A COUPLE OF THESE.
THE FIRST IMPORTANT ONE IS HYDROLASE.
RIGHT, AND SO THIS IS HYDROLYSIS,
THIS IS THE SPLITTING OF PARTS.
SO WHEN YOU SEE HYDROLYSIS, YOU CAN THINK ABOUT IT
BEING CATABOLIC.
AND NOT ONLY THAT, WE CAN THINK ABOUT IT BEING EXOTHERMIC.
SO WE CAN BRING IN ALL OF THE CONCEPTS WE'VE BEEN LEARNING
ABOUT REACTIVITY.
AND SO IN THIS CASE, WE WILL HAVE A BIG LARGE MOLECULE
AND THEN WATER WILL GET ADDED
AND WHEN WE'RE THINKING ABOUT HYDROLYSIS REACTIONS,
IT'S REALLY HELPFUL TO THINK ABOUT WATER AS HOH.
AND THEN WE KNOW THAT THE HYDROXYL GROUP
OF THE WATER WILL BOND TO A PART OF THE MOLECULE,
AND THE HYDROGEN WILL COME IN AND BOND TO THE OTHER PART.
AND SO WE COULD LOOK HERE AND RECOGNIZE THAT
OUR LARGE MOLECULE IS GOING TO BE SPLIT INTO PIECES,
AND WE GET TWO SMALLER MOLECULES.
AND THE OTHER THING TO NOTICE THAT THE WATER,
PART OF THE WATER GOES WITH ONE MOLECULE
AND PART OF THE WATER GOES WITH ANOTHER MOLECULE.
NOW, WE WILL SEE WATER IN THIS NEXT REACTION.
AND SO IT'S IMPORTANT WHEN WE SEE WATER
WE CAN'T GO ON AUTO PILOT AND JUST IT GETS HYDROLASE,
WE HAVE TO LOOK AT THE CHANGES THAT ARE OCCURRING
TO MAKE THE DISTINCTION BETWEEN A HYDROLASE,
AND IN MANY CASES A LYASE WILL INVOLVE WATER.
SO, LET'S LOOK AT LYASE NEXT SO WE CAN COMPARE AND CONTRAST.
THE BIG DEAL WITH THE LYASES, TO KEEP IN MIND,
THAT IT'S ALL ABOUT CARBON-CARBON,
OR CARBON-OXYGEN DOUBLE BONDS, SO THAT'S THE FLAG THERE.
SO UNLIKE THE COENZYMES FOR OXIDOREDUCTASE,
THE DOUBLE BONDS CAN BE OUR FLAG.
TO HELP US RECOGNIZE WHAT TYPE OF REACTION IS OCCURRING.
SO HERE, WE'LL JUST USE A CARBON-CARBON DOUBLE BOND
AND WHO KNOWS WHAT'S GOING ON WITH THE REST OF THE MOLECULE.
AND THEN HERE COMES OUR WATER JUST LIKE BEFORE,
HOWEVER NOW WE NOTICE, RIGHT...
SO THE WATER IS GOING TO MERGE COMPLETELY WITH THIS MOLECULE,
HERE'S OUR CARBON SKELETON AND NOW THE HYDROXYL GROUP
WILL GO WITH THE CARBON ON ONE OF THE CARBONS,
AND THE HYDROGEN GOES WITH THE OTHER CARBON.
SO HERE WE'VE TAKEN TWO MOLECULES
AND WE'VE MADE IT ONE MOLECULE.
SO, I THINK THAT'S ENOUGH TO SAY THERE.
AND SO ITS IMPORTANT TO COMPARE AND CONTRAST
JUST BECAUSE WE HAVE WATER,
WE HAVE TO LOOK AND SEE. SO I'VE GIVEN YOU A COUPLE
OF FLAGS TO HELP YOU DISTINGUISH.
AND NOW, WE'LL LOOK AT ISOMERASE AND VERY LITERAL, RIGHT,
IT'S GOING TO BE AN ISOMERIZATION.
AND SO WE WILL HAVE A COMPOUND, BIOLOGICAL MOLECULES TEND
TO GET VERY BIG.
SO AT A MINIMUM, WE WILL HAVE CARBON HYDROGEN, OXYGEN,
NITROGEN, AND WE MAY POSSIBLY HAVE SOME PHOSPHOROUS AS WELL.
AND THEN WHEN WE LOOK AT THE PRODUCT,
WE WILL SEE THAT WE HAVE THE EXACT SAME NUMBER OF CARBONS,
AND HYDROGENS, OXYGENS, NITROGENS.
SO, YOU MIGHT THINK, WELL, NOTHING CHANGED.
BUT IF WE LOOK MORE CLOSELY, WE'LL SEE THAT THIS HAS
A DIFFERENT CONNECTIONS, DIFFERENT BONDING.
DIFFERENT CONNECTIONS OR SPATIAL ARRANGEMENTS.
SO WHEN WE THINK ABOUT ISOMERIZATION,
WE THINK ABOUT THE TYPES OF ISOMERASE THAT WE'VE LEARNED.
SO THEY CAN EITHER BE STRUCTURAL OR THEY COULD BE STEREOISOMERS.
SO, A LONG TIME AGO, WE TALKED ABOUT DOUBLE BONDS,
IN THE ACTIVE VIEWING OF THIS TUTORIAL,
WE HAVE CIS DOUBLE BONDS, AND TRANS DOUBLE BONDS
INTO CONVERTING TO A TRIGGER NERVE IMPULSES.
SO THAT WOULD BE WHERE WE MIGHT HAVE AN ISOMERASE ENZYME,
CATALYZING THE REACTION.
AND IN OUR BIOCHEMICAL PATHWAYS, WE VERY FREQUENTLY SEE MORE
STRUCTURALIZE ISOMERS, WE CHANGE THE CONNECTIONS OF THE ATOMS.
THE LAST TYPE OF ENZYME THAT WE'RE GOING TO LOOK AT
IS THE LIGASE.
LIGASE IS FRENCH FOR LIGARE WHICH MEANS TO LINK TOGETHER
SO A BOND.
SO WE HAVE A BOND FORMATION AND IT'S COUPLED WITH ATP.
SO THIS IS KIND OF THE OPPOSITE OF HYDROLYSIS.
WE CAN THINK OF THIS AS THEN AS ANABOLIC OR ENDOTHERMIC,
AND IT'S ENDOTHERMIC, RIGHT?
BECAUSE THE REACTION TO BE CATALYZE IS ENDOTHERMIC,
WE COUPLE IT WITH ATP AS THE ENERGY SOURCE,
SO THE ATP WILL THE E SOURCE.
SO SYMBOLICALLY, WHAT IS THIS LOOK LIKE?
WELL, SO IT'S GOING TO BE BASICALLY THE OPPOSITE
OF HYDROLASE.
SO WE HAVE TWO MOLECULES AND TYPICALLY,
ONE OF THEM WILL HAVE A HYDROXYL GROUP
AND THE OTHER ONE WILL HAVE AN IONIZABLE HYDROGEN.
AND SO, WE'RE GOING TO LINK THESE TWO,
COUPLE THESE TWO MOLECULES TOGETHER.
BUT BECAUSE IT'S ENDOTHERMIC, IT WON'T HAPPEN ON ITS OWN.
SO WE BRING IN SOME ATP, AND IT WILL HYDROLYZE TO ADP,
AND IN THE PROCESS, RELEASE ENERGY
WHICH COUPLES TO THIS REACTION SO THAT WE CAN PRODUCE
A LARGER MOLECULE,
AND WE HAVE WATER AS A BYPRODUCT.
SO WE CAN SEE THAT WE TOOK TWO SMALLER MOLECULES
AND WE PRODUCE A LARGER MOLECULE WITH WATER.
SO WHEN YOU GET TO YOUR BIO COURSES,
IT'S REALLY COMMON TO CALL THIS, SYNTHETIC DEHYDRATION.
SO THERE'S MORE THAN ONE FLAVOR OF DEHYDRATION.
SO, THIS IS SYNTHETIC DEHYDRATION
BECAUSE OF THE SYNTHESIS, THE TWO SMALL MOLECULES
INTO THE LARGER MOLECULE.
SO THERE IS THE BIG PICTURE AND INTRODUCTION
TO THE SIX MAIN CLASSES OF ENZYMES.
NOW, LET'S GO BACK AND LOOK AT EACH ONE A LITTLE MORE CLOSELY
AND WITH SOME ACTUAL BIOCHEMICAL REACTIONS.
SO, WE'LL START WITH OXIDOREDUCTASE, RIGHT,
AND THIS WILL BE THE REDOX REACTIONS.
AND SO WE START TO LOOK AND HERE'S OUR FLAG.
OH, LOOK, WE SEE A COENZYME, AND WE LOOK AT OUR SUBSTRATE,
AND WE NOTICE WE HAVE TO LOOK FOR THE CHANGE,
SO WE NOTICE A CARBOXYLATE AND A METHYL GROUP,
THOSE ARE ALL THE SAME, IT'S PRETTY OBVIOUS,
WE HAVE OUR ALCOHOL GROUP AND THE KETONE GROUP.
SO THERE'S OUR CHANGE.
SO LET'S GO AHEAD AND REVIEW. SO WHAT HAPPENED HERE?
WE HAD INCREASE IN OUR CARBON-OXYGEN BONDS,
SO THIS IS DEFINITELY AN OXIDATION.
AND THEN IF WE LOOK AT OUR COENZYME,
WE NOTICE THERE'S NO HYDROGENS THERE
AND THERE'S HYDROGENS THERE, SO WE WOULD RECOGNIZE THIS
AS A REDUCTION.
AND THEN THE LACTATE DEHYDROGENASE,
WE RECOGNIZE THAT AS OUR ENZYME.
SO WE UNDERSTAND EVERY ROLE.
AND SO BASICALLY, WE'VE SEE ABOVE,
WE HAVE IDENTIFIED THE OXIDATION,
AND WHAT THIS IS?
THIS IS LACTIC ACID, RIGHT?
SO LACTIC ACID IS GETTING OXIDIZED TO PYRUVATE,
AND LET'S SEE.
WHAT ELSE DO WE WANT TO DO HERE?
LACTATE DEHYDROGENASE IS THE ENZYME.
WHAT IS THE NAME OF THE TERM GIVEN TO NAD+?
SO, THAT'S RIGHT UP THERE, IT'S THE COENZYME,
SO THAT'S OUR FLAG.
SO THERE'S SEVERAL WAYS TO RECOGNIZE AN OXIDATION
REDUCTION REACTION JUST LOOKING AT THE SUBSTRATE
FOR ITS CHANGE AND THEN THE ROLE OF THE COENZYME
BECAUSE OXIDATION REDUCTION REACTIONS ALWAYS HAPPEN TOGETHER
NOW, LET'S LOOK AT A TRANSFERASE REACTION.
SO, WE'RE NOT GOING TO LOOK AT TRANSFERRING
OF ALL THE DIFFERENT GROUPS,
WE'LL FOCUS, FOR THIS EXAMPLE, ON THE PHOSPHATE GROUP.
SO, IF WE LOOK HERE, WE SEE WE HAVE A GLUCOSE MOLECULE
OFTEN JUST GETS SYMBOLIZED WITH A 'G'.
AND IF WE LOOK HERE, WE SEE WE HAVE GLUCOSE 6-PHOSPATE.
SO WE LOOK FOR THE CHANGE AND WE SEE HERE,
WE HAD AN H, AND NOW WE HAVE THE PHOSPHATE GROUP.
SO WE'VE TRANSFERRED THE PHOSPHATE GROUP,
WHERE DID THE PHOSPHATE GROUP COME FROM?
IT CAME FROM THE ATP.
SO WE HAVE TO BE CAREFUL WITH ATP AS WELL.
NOTICE THAT IN THIS CASE THE ATP IS THE PHOSPHOROUS SOURCE.
SO WE'VE TRANSFERRED THE PHOSPHOROUS FROM ATP
TO THE GLUCOSE.
SO, THE HEXOKINASE IS A TRANFERASE ENZYME.
AND LET'S DRAW THE STRUCTURE OF THE FUNCTIONAL GROUP TRANSFERRED
SO LET'S KEEP IN MIND WHAT PHOSPHATE GROUPS LOOK LIKE
AND WE'LL GO AHEAD AND DO IT AT PHYSIOLOGICAL PH,
AND WE'LL LEAVE ONE OF THESE AS AN ALCOHOL
BECAUSE WE CAN LOOK HERE.
BASICALLY GLUCOSE IS A VERY FANCY ALCOHOL,
AND HERE'S OUR PHOSPHATE, SO IT'S PHOSPHATE ESTER FORMATION,
AND SO THE HYDROGEN OF THE ALCOHOL AND THE OH GROUP,
SO WE WOULD ALSO PRODUCE WATER HERE.
NOW, WE WILL LOOK AT LIGASE.
REMEMBERING LIGARE BOND FORMATION TO LINK TOGETHER.
THE FLAG HERE IS WE'LL ALWAYS HAVE AN ATP-ADP REACTION.
SO, HERE, WE HAVE PYRUVATE AND IT IS GETTING LINKED
WITH CARBON DIOXIDE.
AND THEN WE SEE OUR FINAL PRODUCT HERE.
NOTICE THAT OUR FINAL PRODUCT DOES NOT HAVE ANY PHOSPHATE
ADDED TO IT.
SO WHEN WE LOOK AT ATP HERE, WE SEE IT AS AN ENERGY SOURCE.
THERE'S SEVERAL WAYS THIS COULD BE WRITTEN.
WE MIGHT ALSO SEE THE ATP HERE WITH THE ADP
TO SHOW THAT THEY ARE COUPLED REACTION.
SO, AND WE THINK--LET'S SEE. WHAT ELSE CAN WE THINK ABOUT?
SO, HERE, WE WOULD SAY THIS IS 'A' AND THIS IS B,
AND NOW WE SEE THAT 'A' AND B ARE LOCKED TOGETHER,
BECAUSE MORE ACCURATELY WOULD BE 'B' OVER HERE
AND THEN HERE'S 'A'.
SO THINGS HAD BEEN REARRANGED A LITTLE BIT,
BUT WE SEE THAT WE HAVE LINKED TWO SMALL MOLECULES TOGETHER
TO MAKE A LARGE MOLECULE.
SO, WE'VE TAKEN TWO SMALL MOLECULES,
WE'VE LINKED THEM TOGETHER TO MAKE A LARGE MOLECULE,
AND WE NEEDED ATP AS AN ENERGY SOURCE BECAUSE WE DON'T SEE
THE PHOSPHATE MOLECULE IN OUR FINAL PRODUCT.
SO NOW, THIS WOULD BE A GOOD MOMENT FOR YOU TO REFLECT
ON A WAY THAT MAKES SENSE TO YOU WHEN WE'RE COMPARING
TRANSFERASE TO LIGASE, WHAT CLUES ARE YOU GOING TO USE
TO DISTINGUISH BETWEEN THEM?
SO, FOR ME, WHAT I LOOK AT, IS THAT THE ATP-
IS THE ENERGY SOURCE,
NO PHOSPHATE ON FINAL PRODUCT,
AND THEN WE HAVE TWO SMALLS TO ONE LARGE,
FOR TRANSFERASE, FOR ME, RIGHT?
THE PHOSPHATE, APPEARS BONDED TO THE PRODUCT.
AND IF SOMETHING ELSE MAKES MORE SENSE TO YOU
THEN THAT'S WHAT YOU SHOULD WRITE BECAUSE THESE NOTES
ARE TO HELP YOU.
SO LET'S GO THROUGH A COUPLE MORE OF THE ENZYMES
IN GREATER DETAIL.
LET'S START LOOKING AT HYDROLASE A LITTLE MORE CLOSELY.
SO LIPASE IS A GREAT ENZYME FOR CATALYZING THE HYDROLYSIS
OF FAT.
SO LET'S LOOK HERE.
SO WE WILL CALL THE FAT, OR THE OIL, THE TRIGLYCERIDE,
THE SUBSTRATE,
AND THEN, OF COURSE, WE HAVE WATER
AND I THINK IT'S HELPFUL TO CONTINUE LOOKING AT WATER
AS A HYDROXYL GROUP, AND THEN NOTICE
THAT WE END UP WITH FOUR SMALLER MOLECULES.
WE'LL HAVE ONE GLYCERIN AND THREE FATTY ACIDS.
SO LET'S DRAW A LINE THROUGH THE BONDS AND THE REACTANT,
OR SUBSTRATE THAT ARE SPLIT APART BY THESE WATER MOLECULES,
SO WHERE IN THE FAT DOES THIS WATER COME IN
TO DO HYDROLYSIS, RIGHT?
SO REMEMBER OUR CARBONYLS ARE-- THAT IS WHERE WE CAN GET
OUR BEARINGS AND WE KNOW THAT THE WATER ALWAYS COMES IN
BETWEEN THE CARBONYL AND THE HETEROATOM.
SO THIS IS WHERE THE WATER IS GOING TO COME IN,
IT'S GOING TO GIVE AN H TO THE ALCOHOLS,
AND THE CARBONYL ALWAYS GETS THE 'OH', ALL RIGHT.
WE'VE DRAWN IN THE LINE TO SHOW WHERE THE BONDS ARE BROKEN.
NOW, LET'S LOOK AT THE PRODUCTS, LET'S CIRCLE THE HYDROXYL GROUPS
IN THE PRODUCT THAT WERE DERIVED FROM THE WATER MOLECULES
SO, THAT WOULD BE RIGHT HERE.
SO FROM THE WATER, THERE ARE THE HYDROXYL GROUPS
THAT CAME BECAUSE WE KNOW THAT THE HYDROXYL GROUPS
ALWAYS CONNECT WITH THE CARBONYL CARBON.
NOW LET'S BOX THE HYDROGEN ATOMS THAT CAME FROM THE WATER,
AND SO THOSE WOULD BE RIGHT HERE,
THERE WE GO. OKAY.
SO THAT'S ABOUT IT THERE, RIGHT.
SO WE HAD A LOT OF EXPERIENCE WITH HYDROLYSIS REACTIONS.
SO, WE RECOGNIZE THE ESTER BONDS,
HYDROLYZED TO CARBOXYLIC ACIDS AND ALCOHOLS.
SO NOW, LET'S LOOK AT LYASE, ANOTHER ENZYME THAT FREQUENTLY
HAS WATER AS A REACTANT.
SO WE LOOK HERE AT CARBONIC ANHYDRASE,
SO WE HAVE CARBON DIOXIDE AND WATER, RIGHT.
SO WITH LYASES, THEY CATALYZE THE ADDITION OF GROUPS,
WATER IS VERY FREQUENT, WE COULD SEE C02, OR AMMONIA,
REMEMBER THE KEY WITH LYASE IS IT'S A DOUBLE BOND.
AND REMEMBER THAT WHEN WE TALK ABOUT ENZYMES,
THEY COULD BE FORWARD OR REVERSE,
SO WE COULD EITHER ADD TO A DOUBLE BOND
OR IN THE REVERSE REACTION, WE COULD FORM A DOUBLE BOND.
SO REMEMBER TO THINK ABOUT THINGS BOTH WAYS.
SO HERE, LET'S MOVE THE WATER OVER TO MAKE IT
A LITTLE EASIER TO SEE, AND LET'S LOOK AT OUR--
SO HERE'S OUR INITIAL REACTANTS AND HERE'S OUR PRODUCTS.
SO THIS ONE CAN SEEM A LITTLE CRAZY
BUT WELL HERE'S OUR CARBON.
SO LET'S LOOK AT WHAT HAPPENS HERE,
AND WHAT HAPPENS IS, WE SEE THAT OUR CARBON IS
GOING TO HAVE A NEW HYDROXYL GROUP.
SO THIS IS GOING TO COME HERE. AND WE NOTICED THAT NOW,
THERE'S ONLY ONE CARBON TO OXYGEN DOUBLE BOND.
ONE OF THE CARBON TO OXYGEN DOUBLE BONDS
BECOMES A HYDROXYL GROUP.
SO THE ENZYME CREATES BOND FORMATION WHERE WE'VE SHOWN
WITH THE RED ARROWS AND THEN THAT LEADS US
TO OUR FINAL PRODUCT.
SO WE CAN SEE HERE THAT WE HAVE ADDED WATER TO A CARBON
TO OXYGEN DOUBLE BOND.
AND IT COULD ALSO BE CARBON-CARBON DOUBLE BONDS
BUT THIS ONE IS A GOOD EXAMPLE.
SO LET'S KEEP THAT IN MIND UP HERE,
SO THE DOUBLE BOND COULD BE CARBON-CARBON
OR CARBON-OXYGEN, AND SO THEN WE CAN KEEP TRACK.
THIS WAS FROM WATER, SO NOTICE ONCE AGAIN,
THAT WHEN WE STARTED, WE HAD TWO MOLECULES, RIGHT?
ONE OF THOSE MOLECULES WAS WATER AND WE ENDED UP
WITH ONE LARGER MOLECULE.
SO WE'VE USED THAT DESCRIPTION A COUPLE TIMES,
HOWEVER NOTICE THOUGH THAT HERE, WATER IS ONE OF THE MOLECULES
THAT'S ADDED ACROSS AND WE HAVE THE FEATURE
OF THE DOUBLE BONDS.
IN THE PAST, IT'S FREQUENT FOR STUDENTS TO HAVE
A LITTLE BIT OF TROUBLE DISTINGUISHING BETWEEN
HYDROLASE AND LYASE.
SO NOW IS THE TIME FOR YOU TO WRITE SOME COMMENTS TO YOURSELF
THAT HELP YOU DISTINGUISH BETWEEN THESE TWO ENZYMES.
WHAT HELPS ME HERE TO GUIDE YOU, RIGHT?
SO FOR ME, THE WHOLE POINT OF HYDROLASE-
WE CAN THINK ABOUT THAT IT'S CATABOLIC,
IT'S REALLY THE OPPOSITE, RIGHT?
WATER SPLITS APART TWO MOLECULES OR SPLITS APART A MOLECULE,
INTO TWO SMALLER MOLECULES.
VERSUS LYASE, RIGHT?
SO WHAT'S GOING ON WITH LYASE?
SO WITH LYASE, BASICALLY, IT'S THE WATER BONDS
TO THE SUBSTRATE
AND WHERE DOES IT BOND TO THE SUBSTRATE,
AT A CARBON-CARBON DOUBLE OR A CARBON TO OXYGEN DOUBLE BOND,
SO THAT'S THE MAIN WAYS TO DISTINGUISH BETWEEN
HYDROLASE AND LYASE.
SO NOW, WE'LL LOOK AT THE LAST CLASSIFICATION OF ENZYMES,
THE ISOMERASE
AND THEN WE'LL JUST PRACTICE IDENTIFYING AND CLASSIFYING
ENZYMES IN A VARIETY OF REACTIONS,
SO THE LAST ONE HERE, WE HAVE TWO MOLECULES
AND WE LOOK AT THEM, AND AS WE START TO SCAN THEM,
IT'S LIKE, HMM, I SEE A CARBOXYLATE,
WE SEE A HYDROXYL, I SEE A PHOSPHATE,
OFTEN YOU CAN GO, HMM...
I'M NOT SEEING ANY DIFFERENCES.
THERE'S THE MINUS CHARGE, RIGHT?
SO I'M NOT REALLY SEEING ANY DIFFERENCES.
SO WHEN YOU FEEL STUCK LIKE, "HUH? I DON'T SEE ANYTHING
DIFFERENT."
DO A QUICK INVENTORY.
WE'LL SEE THAT WE HAVE THREE CARBONS, FOUR HYDROGENS,
SEVEN OXYGENS, AND A PHOSPHORUS WITH A NET CHARGE OF -3.
IF WE START COUNTING ATOMS ON THE RIGHT,
ONE, TWO, THREE. ALL RIGHT.
SO C3, H4, O7, PHOSPHORUS 3-.
SO NOW, WE SEE WHAT HAPPENED.
WE HAVE THE SAME CHEMICAL FORMULA
BUT WE HAVE DIFFERENT CONNECTIONS.
SO THE RELATIONSHIP BETWEEN THE SUBSTRATE AND THE PRODUCT
WOULD BE THAT THEY ARE STRUCTURAL ISOMERS, RIGHT?
MAKING SURE EVERYBODY FEELS COMFORTABLE WITH THE LANGUAGE.
SUBSTRATE AND PRODUCT.
AND SO IN THIS CASE, IF IT WAS GEOMETRIC,
THAT WOULD BE A SPATIAL ARRANGEMENT DIFFERENCE.
BUT HERE, WE HAVE DIFFERENT CONNECTIONS
SO THEY'RE CONSTITUTIONAL OR STRUCTURAL ISOMERS.
SO WE'VE GONE THROUGH THE SIX MAJOR CLASSIFICATIONS
AND THEY'RE WRITTEN OUT FOR YOU RIGHT HERE.
AND NOW, WE HAVE SIX REACTIONS TO LOOK AT,
WELL, WE'LL JUST HAVE TO-- THERE WE GO AGAIN.
WELL, I CAN'T QUITE GET THEM ALL.
SO, NOW WE WANT TO PRACTICE, SO THIS WOULD BE A GOOD TIME
TO PAUSE THE VIDEO AND PRACTICE CLASSIFYING THEM
ON YOUR OWN, AND THEN WE CAN COMPARE YOUR ANSWERS WITH MINE.
LET'S LOOK AT THIS FIRST ONE.
IT CAN BE VERY HELPFUL TO CIRCLE WHERE WE SEE A CHANGE.
SO WE LOOK FROM LEFT TO RIGHT, I'M LIKE, HMM...
THERE'S A DOUBLE BOND HERE, AND THERE'S NO DOUBLE BOND HERE,
BUT I DO SEE THE ADDITION OF WATER, RIGHT?
SO WE HAVE TWO MOLECULES FORMING A LARGER MOLECULE
AND WITH A DOUBLE BOND,
SO LYASE, SO WE WOULD NEED A LYASE ENZYME TO CATALYZE
THIS REACTION.
NOW WE SEE ANOTHER EXAMPLE WITH WATER PRESENT.
THIS MOLECULE IS UREA, AND WE NOTICED THAT UREA REACTS
WITH WATER AND NOW WE HAVE THREE MOLECULES.
SO WHAT HAS HAPPENED?
SO, WE SEE HYDROLYSIS HAPPENING AND WE WOULD ACTUALLY--
THIS ISN'T BALANCED, WE WOULD NEED TO ADD
SOME MORE WATER HERE, I THINK WE WOULD NEED TWO WATERS,
SO THE WATER IS COMING IN AND IT IS SPLITTING APART THE UREA,
SO WE'VE GONE FROM A LARGE MOLECULE,
TO SMALLER MOLECULES.
AND REMEMBER EVERYTHING'S RELATIVE.
I KNOW UREA DOESN'T LOOK THAT BIG COMPARED TO SOME THINGS
WE'VE BEEN STUDYING,
BUT IF WE COMPARE ITS SUBSTRATE TO PRODUCTS,
IT'S THE BIGGEST MOLECULE IN THIS REACTION.
SO THIS IS DEFINITELY AN EXAMPLE OF A HYDROLASE.
WE'LL GO TRY NEXT EXAMPLE, WE LOOK HERE,
AND WE SEE, OKAY, THERE'S AN ALCOHOL,
OOH, HUH?
DID IT GET OXIDIZED?
LET'S KEEP LOOKING.
BUT THEN WE SEE A CARBONYL AND AN ALCOHOL, HMM.
SO THIS DOESN'T APPEAR TO BE OXIDATION AND REDUCTION
BECAUSE OUR SUBSTRATE HAS A HYDROXYL AND A CARBONYL,
AND OUR PRODUCT HAS A HYDROXYL AND A CARBONYL,
AND THEN PHOSPHATE GROUPS.
SO THERE'S NO OXIDATION AND REDUCTION,
AND THERE'S NO COENZYMES. HMM,
SO OFTEN WHEN I'M STUCK, THEN WE GO--
OH, YES. ISOMERASE, RIGHT.
NOTHING HAS CHANGED, WE'VE SIMPLY REARRANGED THE PARTS,
LET'S LOOK AT REACTION D, HERE WE HAVE PYRUVATE
AND CO2... OH, YEAH, AND THIS ONE'S FORMATTED
A LITTLE DIFFERENTLY.
WE CAN SEE THESE PARTS ALL THE SAME HERE,
AND THEN HERE'S OUR CO2, AND WE CAN SEE THE CARBOXYLATE,
SO WE HAVE TWO SMALL MOLECULES, WE'VE LINKED THEM TOGETHER
TO MAKE A LARGE MOLECULE,
THE PHOSPHATE, NOWHERE TO BE SEEN,
SO WE RECOGNIZE THIS AS A ENERGY SOURCE
AND THIS WOULD BE--
SO PYRUVATE CARBOXYLASE IS A LIGASE ENZYME,
LIGARE, LINKING TOGETHER.
LET'S LOOK AT REACTION E.
WE START HERE.
WE HAVE TWO CARBON CHAIN WITH AN ALCOHOL,
OH, THERE'S OUR COENZYME.
WE PRETTY ALREADY KNOW WHAT THIS IS GOING TO BE,
BUT LET'S FOLLOW UP, RIGHT?
WE GO FROM AN ALCOHOL TO AN ALDEHYDE.
SO WE HAVE OXIDATION AND WE HAVE REDUCTION.
SO THIS WOULD BE AN EXAMPLE OF THE OXIDOREDUCTASE.
AND THEN OUR LAST EXAMPLE HERE, WE LOOK AND WE SEE,
WE HAVE OUR BUDDY GLUCOSE, AND WE LOOK OVER HERE,
SO THAT'S NOT GLUCOSE 6 PHOSPHATE, RIGHT?
BUT THERE'S A GLUCOSE PHOSPHATE THERE,
GLUCOSE 1 PHOSPHATE SO WE'VE ADDED A PHOSPHATE GROUP
TO GLUCOSE.
SO HERE, THE ATP IS NOT AN ENERGY SOURCE-
I MEAN, THERE'S STILL SOME ENERGY SHARED
BUT REALLY, WE'RE FOCUSING THAT IT'S THE PHOSPHATE SOURCE.
AND SO, WE WOULD CLASSIFY THIS ENZYME AS A TRANSFERASE.
WELL, THAT CONCLUDES OUR TUTORIAL
ON CLASSIFYING ENZYMES.
PLEASE TAKE SOME TIME NOW TO WORK A FEW HOMEWORK PROBLEMS
TO REINFORCE YOUR UNDERSTANDING.