Questions tagged [enzymes]

Enzymes are globular proteins that catalyse 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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Photolysis in the Light Reactions of Photosynthesis [duplicate]

I'm a bit confused concerning photolysis. During the light reactions, photons are used to excite the chlorophyll molecules so they are passed to the primary electron acceptor. The electrons initially ...
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Cellulase Sample Digestion Protocol?

Is there an effective way to use cellulase(s) and/or lignase(s) to remove unwanted plant debris from a sample? I'm working with a series of fresh water grab samples for environmental assessment. The ...
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How is plasmin formed from plasminogen?

In Ganong's Review of medical physiology it is mentioned that plasminogen is converted to active plasmin when tissue type plaminogen activator hydrolyses the bond between Arg560 and Valine 561. Can ...
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How can we digest lactose even though it has Beta glycosidic linkages?

I have Read that we cannot digest cellulose because we do not have enzymes to digest Beta glycosidic linkages in Cellulose Then how is it that we have an enzyme called Lactase to digest the Beta ...
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Can enzymes be modeled using classical mechanics?

When enzymes interact with substrates (i.e. a small ADP molecule and the much larger ATP synthase), does quantum mechanics play a significant role? Or can the interactions be relatively accurately be ...
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What happens if an enzyme stops working in the body?

For example, if the enzymes in the digestive system stop working will the digestion still occur as enzymes are only catalysts for the reactions. Thank You
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Looking for a good and complete Enzimology exercises book

I mean, I want to practice with challenging exercises and I want to know the theory behind them. So, I started reading: Organic Chemistry: Yurkanis, P. Enzyme kinetics: Bisswanger, H. Biotechnology ...
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Cheap enzyme assay for a high school lab

At the moment, I'm designing an experiment for a high school lab with no financial resources. I need to assess the impact of a variety of factors on a specific enzyme's reaction with its respective ...
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Where is catalase produced?

I am doing a research project on the peroxisomes, and in it I referenced the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen. However, the assignment asks me to specify the ...
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How does the helicase enzyme break the hydrogen bonds between the strands of DNA?

I know helicase breaks the hydrogen bonds between the strands of a DNA, but how is this done? Does it put an ion between the strands of the nucleic acid so that the bond breaks apart itself or is ...
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Speed of reaction vs equilibrium

Does increasing the speed of a reaction (say by introducing a catalyst) shift the equilibrium of the reaction? I assume it does not, as Gibbs free energy is not changed, but I am not sure.
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Do there exist enzymes that can take up multiple cofactors to do different reactions?

I was thinking about enzyme catalysis, and it seems like enzymes can only catalyse one kind of forward/reverse reaction (please correct me if I am wrong). Does there exist an enzyme that can catalyse ...
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What are the marker enzymes for Nucleus, Ribosomes and cell membrane?

Are there any marker enzymes present for ribosomes, nucleus and cell membrane. For mitochondria there are many, for lysosome it's cathepsin. I read about the marker enzymes of most of the other ...
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May two reactions, that share the same reactant, fire at the same moment?

I'm studying metabolic networks from a bioinformatics point of view, but I guess my question is pretty biological so I thought that maybe here I could get the best answers. So, as the title says I ...
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Will amylase inhibitors affect the colorigenic reaction between starch and iodine?

I'm doing an experiment for my IB bio EE involving colorimetry. I'm not experienced at all with colorimetry, so I'm having some trouble planning it. The experiment is on enzyme kinetics, and I'm ...
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Why is the GULO pseudo gene expressed in humans?

The GULO pseudo gene is being expressed in humans according to Genecards. Why is this still taking place after tens of millions of years since then gene lost the capacity to encode for a functional ...
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What enzyme or bacteria could dissolve plastic?

What enzyme or bacteria could dissolve plastic aside from acetone? Preferably, low-cost and environmentally friendly. Any suggestions would be helpful. I'm targeting for thin plastic (low-density ...
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Cooperative Enzyme Question

I'm currently studying for the MCATs. After doing some biochemistry practice questions, I came upon a question that I believe may be incorrectly posed. I was wondering if I'm correct in saying this or ...
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How do NSAID's work and what are the differnces between COX-1 and COX-2? [closed]

NSAID's work by slowing down the COX enzym, but how do does enzymes cause pain? because I've read that they're also needed for the body and do "good" things.
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How could pharmaceutical metabolizing bacteria be used to synthesize them?

Lets say I have a pharmaceutical "P". It can be broken down by enzymes of one strain of bacteria into two molecules one of which can be further metabolized enzymatically by a different strain of ...
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which enzyme phosphorylates sodium potassium pump?

I know that Na+/k+ pump possess atp-ase function; so the pump will hydrolyze ATP into ADP + Pi. And I see in a figure that the pump is phosphorylated but couldn't really find which protein catalyzes ...
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Does digestion require hydrochloric acid?

Would our digestion function any differently if we secreted something else, like sulfuric or nitric acid, instead? I'd assume an acidic environment may be required, but not sure if chloride is also ...
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How do fatty acid and polyketide synthases handle the varying size of their substrates?

Polyketide synthesis involves six modules, each containing certain common constituent enzyme activities (KS, AT, KR) that are involved in extending the chain (see e.g. Dutta et al.(2014) ). The ...
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How can P450 distinguish between foreign and native compounds?

It is my understanding that P450 enzymes are capable of selectively degrading compounds that enter the cell from the outside (e.g. synthetic drugs) without damaging compounds that are metabolic ...
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How long does an enzyme work?

I googled this, and I found only that shelf lives are around 2-3 years, but the enzymes use to work even after 5 years if you store them properly. I'd like to know how long I can use an enzyme in ...
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How do DNA, enzymes, hormones etc. reach their proper cellular locations?

I was trying to understand DNA transcription from this chapter, and there seems to be no explanation on how exactly the proteins, enzymes and other molecules manage to find each other inside the cell. ...
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Enzyme inhibitors against common cold viruses

Would some inhibitors of viral enzymes work against common cold viruses? Are there any studies? What could a treatment look like? A lot of common cold viruses are rhino viruses which are picorna ...
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Which enzyme is Nick Lane referring to?

In Life Ascending the author, Nick Lane, refers to an enzyme in his introduction: '' It concerns an enzyme (a protein that catalyses a chemical reaction) that is so central to life that it is found ...
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Do we know how dangerous six-eyed sand spiders are?

The Sicariidae family contains the well-known and dangerous Loxosceles spp. (fiddle-backs, violin spiders). The family's other two genera, Sicarius and Hexophthalma (six-eyed sand spiders) have ...
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Are all enzymes proteins?

So throughout my education and research career I have been taught that all enzymes are proteins. This makes sense when you consider enzyme denaturing and folding/shape etc. However, I was recently ...
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Are there any enzymes without aromatic amino acids?

I'd like to try a new spectroscopic technique to study enzymatic reactions (which reaction doesn't especially matter, something simple and with fast kinetics like catalase would do fine - I'm just ...
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How to calculate the turnover number?

I understand that Kcat (turnover number) = Vmax/total enzyme concentration. However the formula I have been given is Kcat = specific activity/molecular mass of enzyme. What is the relationship ...
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How can we quantify the effect of pancreatin (biological enzyme) on the clarification of milk powder

Alright so I'm trying to quantify the rate at which casein (protein constituent of milk powder) is converted into a product (I am unaware of) by pancreatin (a biological enzyme that speeds up the ...
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What are the effects of enzyme exposure to high temperatures? [duplicate]

Question: After enzymes are exposed to high temperatures and undergo denaturation, then returned to their optimal temperature and renatured, can the enzyme's active site return to it's original shape ...
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Why does M1 RNA together with C5 protein in 100mM Mg(II) fail to cleave tRNA?

Sidney Altman discovered that RNA moeity of RNAse P (M1 RNA) alone is able to perform enzymatic cleavage of ptRNA, which won him the Nobel Prize of Chemistry in 1989. However, when I read the Nobel ...
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Michaelis Menten kinetics - Plotting to find V-max and Km [closed]

In dealing with the question above I know that if we plot 1/v against 1/[isocitrate] we can get V-max = 1/intercept and Km = slope/intercept. However when I express the two rows of values in ...
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Why are plants unable to take up Phosphorus directly in their organic form like Phytic Acid?

I am researching acquisition strategies of phosphorus by decidious trees. I am reading a lot that plants take up nutrients as their inorganic form. In the case of P according to literature this is ...
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Question about vitamin b6 product and cycling

Can the b6-product of a vitamin b6 reaction such as transaminase be recycled back to active vitamin b6 in man, and if so by means of what reaction?
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Is egg white lysozyme different from bacterial lysozyme?

Someone told me that microbial lysozyme has effect on gram negative bacteria but egg white lysozyme only affect gram positive bacteria. Is it true?
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Molecular Docking Enzyme Inhibitor Biosensor?

I had some task to study Molecular Docking relations with Biosensor and I am really new with this discipline (beginner). I am docking C60 with Glucose Oxidase and my question is: what would happen if ...
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Why don't phosphatases both add and remove phosphate groups if enzymes catalyze reactions in both directions?

We know that Phosphatase is a type of enzymes that removes a phosphate group. Why can't phosphatases add a phosphate group if we know that all enzymes reactions are reversible ?
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Michaelis-Menten equation; how to find the constants from enzyme activity experimental results?

I was wondering what the constants in the Michaelis-Menten equation actually mean in experimental data of enzymes. How do I process the data to find Km and Kcat? I did an experiment on catalase and ...
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How can enzymes be immobilised on glass?

I’m studying a hypothetical model for urease activity, which involves fluorescence measurement, hence the need for an optical window to which the enzyme urease is immobilised. From my previous ...
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Can experiments in ELISA kits be monitored via both fluorometry and photometry?

In my bioanalytics course slides, the professor has written at one point that in a heterogenous immunoassay such as ELISA, we use fluorimetry to measure concentration of an analyte. In another slide ...
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What does “operationally soluble” mean, re. Tax10 enzyme?

I am trying to work out whether the enzyme Tax10 is soluble or insoluble. I need to know if some buffers won't work with Tax10. I am trying to confirm Tax10 activity, having confirmed protein ...
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How do metal ions acting as enzyme cofactors “find” their respective enzymes?

Metalloproteins are metal-dependent proteins, i.e. they require certain metal ions (copper, magnesium, zinc, etc.) for their correct function in the body. Since proteins are manufactured inside cells ...
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How to convert between Kunitz units and Enzymatic units?

I've googled around and there has been the common answer of 1.5 U = 1 Kunitz Unit, but none of those answers have come from a reputable source, so I am really doubtful. :( The enzyme I use comes in ...
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What options exist to quantitatively detect enzyme activity in non-model insect tissue?

Evolution/genomics person here: what are the options to measure the activity or presence of broad categories of enzymes--like peroxidases or catalases--active in a specific tissue (in a non-model ...
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Why is pepsin able to operate at low pH?

Pepsin is a protease that operates in the acid pH of the stomach. Many proteins are denatured at low pH, and most enzymes — whether or not they denature — require a higher pH for activity. Why is ...
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Is this experiment to check enzyme reaction rate according to substrate concentration correct?

We just had an experiment to check enzyme reaction rate according to it's substrate concentration. In the experiment, we used a varying amount of substrate and the same amount of enzyme: (1.5mm enz, ...

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