Enzymes are globular proteins that catalyze a biochemical reaction, increasing the overall rate by reducing activation energy. Most chemical reactions in a cell need enzymes in order to occur at rates sufficient to sustain life.

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Difference between negative allosteric regulation and non-competitive inhibition

Both connect to some site other than the active site which controls the shape of the active site and causes the enzyme to be less active. So what is the difference?
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30 views

Aspirin - does it inhibit enzyme of thromboxane?

This is a diagram a friend showed me about the drug aspirin, where we were arguing which enzyme it prevents. Aspirin is known to inhibit the production of prostaglandins. However, it also serves ...
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2answers
19 views

Can an enzyme be activated without allosteric inhibition or activation?

Are there ways by which an enzyme may be activated or inhibited by non substrate molecules other than allosteric activation or inhibition?
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39 views

What are some enzymes that can be active without cofactor? [closed]

While reading through a section about cofactor I came across the fact that some enzymes require cofactors. What are some examples?
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7 views

Is there a deblocking aminopeptidase without normal aminopeptidase activity?

The deblocking aminopeptidase is a unique exo-type aminopeptidase that liberates blocking groups (formyl, acetyl, and myristyl) from proteins and peptides. However, according to this paper, it has two ...
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21 views

Is it possible to separate the binding and catalysis of an enzyme in two steps?

Is it possible to do the following: Enzyme E binds to its substrate S without catalysis; Add a controllable stimulus, such as light, adding or removing chemicals; The enzymatic reaction is triggered ...
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49 views

Do we actually know the molecular dynamics of any enzyme?

That is right, is there a limitation, say Heisenberg's uncertainty principle or something that limits our understanding of machinery of enzymes at atomic level? Can we know how do they actually work? ...
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42 views

sodium chloride and amylase activity

So, I did an experiment on the effect of sodium chloride on amylase. and I found out the higher the concentration, the slower the activity. Therefore, is it valid to make the assumption that when we ...
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32 views

How to calculate the LOB, LOD and LOQ of an enzyme assay

I understand how to calculate limit of blank (LOB), limit of detection (LOD), and limit of quantitation (LOQ) in the traditional way i.e., average and SD of raw analytical signal of blanks and low ...
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33 views

Why is binding energy the difference between ∆G catalyzed and ∆G uncatalyzed?

I think the title explains it pretty well -- I'm confused on what 1) exactly binding energy is 2) and why it's the difference. Like in this diagram: my teacher sort of said it was the energy the ...
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17 views

Will a metalloenzyme bind to its substrate in the absence of its metal ion cofactor?

A metalloenzyme is an enzyme using a specific metal ion as its cofactor. Their activity is dependent on this metal ion. For example, the T4 DNA ligase requires Mg2+ to ligate DNA strands; The ...
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3answers
36 views

Is there a database providing information about optimum temperature and inactive temperature of enzymes?

I want to know optimum and inactive temperature of some enzyme, but I can't find these information in NCBI, wiki or UniProt. So I want to know if there are some database which provide these ...
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42 views

Proteases in the blood

I’m reading on hormones and the book talks about how peptide or amine hormones are easily broken down by proteases present in the blood plasma. This has led me to question the interactions between ...
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19 views

What's the purpose of Cdk activity having more than one method of becoming inactive?

Cdk becomes partially active once its bound to cyclin and then gets phosphorylated and fully active once a Cdk-activating kinase (CAK) phosphorylates the partially active Cdk. This fully activated Cdk ...
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2answers
15 views

Affinity Column of membrane bound receptors

I understand affinity columns can be used to study the ligand/enzyme affinity. But is an affinity column able to be used for membrane bound receptors? I
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33 views

What cures pineapple burns?

If you already ate too much bromelain in pineapple, how do you cure your tongue burn?
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28 views

Invertase calculation?

If I wanted to make $500\mathrm{\mu g}/\mathrm{ml}$ of invertase, from Sigma's Invertase from Baker's yeast, which states is grade VII, and greater than or equal to $300 \mathrm{units}/\mathrm{ml}$, ...
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44 views

Enzymes and cofactors

About how much % of the human enzymes need cofactors? Like 20%, 30%, or 50% of a cell's enzymes? And how many enzymes work "alone"? This is a general question to figure things out. Do most enzymes ...
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151 views

Why is it often the case that an enzyme is favorable only towards one direction of a reaction and not both directions?

In class when we're studying enzymes like amylase or protease it only works well when you're using it to break down compounds like polysaccharides. I'm just curious but why is it not possible for ...
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78 views

What is a detailed chemical explanation for describing how an enzyme may lower the activation energy of a reaction?

If you can provide some sound reasoning that touches on tertiary structures of proteins and does not use a lot of advanced chemistry jargon that might be really helpful, especially for an intro ...
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101 views

Can any enzyme be produced?

After reading about how recombinant insulin is produced, the following question occured to me. Does the current level of technology allow any enzyme to be produced in a similar way? As I see, ...
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90 views

How will changing the concentration of a Tris buffer affect amylase enzyme activity?

For instance if you increase the amount of Tris but pH still does not change then will the enzyme activity still proceed normally? If it does change the pH will it change enzyme structure and why?
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1answer
95 views

Dwell time equations for ATP-sythase?

I have read that every 120 degree rotation of the F1 complex of ATP-synthase can be split into a 30 degree rotation and a 90 degree rotation. In between these two are dwell times, the one before the ...
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30 views

How is Glycophorin A and straphylococcal related to Escherichia coli and what does readily purified mean in this context?

I am reviewing the paper "Glycophorin A Dimerization Is Driven by Specific Interactions between Transmembrane Alpha-Helices." There is a statement in the abstract which I don't understand: "The ...
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37 views

Nagalase testing any good?

Is Nagalase testing good to detect if something is wrong in the body (ex: cancer)? The next problem I assume would be to know what/where the problem is. To put it an other way: If I understand ...
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1answer
172 views

Do the enzymes and compounds in saliva help with stain removal?

Does spitting on stains help with removal? Saliva is high in amylase that should help with the breakdown of protein rich stains like blood and semen. It also contains antimicrobial enzymes and ...
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1answer
37 views

Is NADPH unstable in UV light?

I am working on an enzyme activity assay using NADPH as a cofactor. The MSDS for NADPH Tetrasodium Salt, tells to store it in a place away from heat and light. Does this include UV light or just ...
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226 views

How is the subunit molecular weight different from the native molecular weight?

I noticed that the native molecular weight for an enzyme is different from its subunit molecular weight. Why are they different? Aren't the genes needed to express the enzyme the same in the native ...
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43 views

Proline Iminopeptidase v Proline Aminopeptidase

We're an undergraduate independent research team and we are having trouble purchasing commercial proline iminopeptidase as it is unavailable on Sigma Aldrich and very expensive on other websites. We ...
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394 views

The effect on the efficacy and potency of a non-competetive antagonist binding to the active site of the receptor (dose-response curve)

According to the book "Principles of Pharmacology: The Pathophysiologic Basis of Drug Therapy" by Golan et al, non-competetive antagonists can bind to both the allosteric site and the active site. I ...
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60 views

Do non-enzyme catalysed reaction pathways exist?

Can their be a kind of chemical reaction pathway in a cell, that is catalyzed or regulated but NOT necessarily by enzymes? I could not find anything on Google. I have almost no background in biology, ...
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50 views

Applying kiwis on gelatin

Kiwis have the enzyme actinidain. This enzyme will break the peptide bonds from the gelatin. Making gelatin with raw kiwis will not work, because the peptide bonds in the gelatin will be broken down. ...
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85 views

How can human infants express chymosin with only a pseudogene at their disposal?

I read on the Wikipedia article about Chymosin http://en.m.wikipedia.org/wiki/Chymosin It stated that chymosin is produced by gastric chief cell in human infants. But it also stated that human only ...
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40 views

Where does the oxygen and water produced from the decomposition of hydrogen peroxide by catalase enzyme go?

How are they disposed of by the body, or are they disposed of at all? Since our body needs water and oxygen anyway, I'm speculating that these "waste product" will be reused/recycled by the body in ...
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77 views

Medical Uses of toxic venom

One interesting thing I recently learned is that venom has medical uses that can actually save lives! But from what I see so far this either applies to venoms from creatures that are not fatal to ...
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130 views

Hydrogen peroxide decomposition and catalase uses [closed]

All google searches have simply returned more info on catalase. I'm looking for a catalyst that isn't found inside living organisms which can break down H2O2. Looking for any resources to look at, or ...
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98 views

Is there a DNA analogue to ribozymes? [duplicate]

If not, is it impossible for DNA to have enzymatic activity?
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1answer
19 views

Are the proteolytic enzymes in syconiums and nettles identical to those in rennet?

I would like to compare rennet capability under various conditions. The issue is, I don't want to use calf rennet, but I can't figure out if nettle and syconium, which also coagulate milk, contain ...
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113 views

Enzymatic error rate

I am aware that each enzyme generate a certain amount of misproducts. This is well documented, for example, for the DNA polymerase. I am interested in enzyme involved in biochemical processes, so for ...
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1answer
842 views

Making the sense of enzyme Km comparisons

I have encountered comparisons of the Michaelis-menton constant (Km) a few times. Generally speaking if Km of an enzyme is higher, then it's affinity to its substrate is lower. How does this make ...
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1answer
91 views

Mode of Enzymatic Inhibition via R-Allele

The photo above shows the effects of the R allele of the pea shape gene on the synthesis of an enzyme that converts unbranched starch into branched starch. The r allele of this gene determines an ...
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890 views

Grapefruits and CYP3A4

Grapefruit juice contains furanocoumarins, which irreversibly inhibit CYP3A4. For this reason, when one is taking certain medications it is necessary to not eat grapefruits because the inhibition of ...
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1answer
438 views

How does salinity affect the bonds of an enzyme?

According to my textbook, "Too much or too little salt can interfere with the hydrogen bonds that hold an enzyme in its three-dimensional shape". I know that NaCl is held together by an ionic bond, ...
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1answer
100 views

How do catalase and other antioxidants neutralize free radicals?

In learning about how cofactors are essential to proper enzyme function, my textbook mentioned catalase and its relation to the human body. According to my textbook, catalase is similar to hemoglobin ...
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2answers
840 views

How to inactivate trypsin permanently by boiling?

I have to perform a hydrolysis of BSA with the enzyme trypsin. As a control I want to inactivate the trypsin enzyme. Can I inactivate it permanently by boiling (100oC) for 10 minutes, or does it it ...
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1answer
2k views

What is the difference between a phosphotransferase, a phosphatase, a phosphorylase and a kinase?

I've looked in several sources, but I'm still confused. This is what I have so far: A phosphotransferase catalyzes the addition of a phosphate group. A kinase is a type of phosphotransferase that ...
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44 views

Alkaline Phosphatase

What is the predominant purpose of Alkaline Phosphatase in skeletal muscle fibers and liver cells. I know that it is a hydrolase enzyme that speeds up the degredation of proteins, lipids, starch and ...
3
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1answer
397 views

Is the activity of enzymes in the human body affected by the outer temperature?

I have to do a research about the enzymes in the human body and the things that affect them. I know that the body temperature affects the activity of enzyemes but I'd like to know if the outer ...
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2k views

What is a catalytic domain of an enzyme?

Is this another name for the active site of an enzyme? What does the structure of the catalytic domain of an enzyme look like?
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Does “Garbage Enzyme cleaner” contain cleaning enzymes?

There are many recipes which call for using fruit peel fermentation process to make a concentrated enzyme cleaner solution, some variations call to add bakers yeast. So the question arises that does ...