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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What is the dynamic range under initial conditions?

could someone help me to understand the following sentence better? It's from the book "A Practical Guide to Assay Development and High-Throughput Screening in Drug Discovery". And it's about ...
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Can enzymes be externally administered?

I was reading about Tay Sachs disease - it is essentially the deficiency of the enzyme hexosaminidase. Why can't the disease be treated by administering the enzyme (prepared artificially/extracted ...
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Why does ATP act as an allosteric inhibitor of glycogen synthase?

Why is ATP an allosteric inhibitor of glycogen synthase? Wouldn't high levels of ATP in the cell mean that the cell has sufficient energy, and in this case wouldn't excess glucose be stored as ...
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What determines the nucleotides incorporated into RNA by polynucleotide phosphorylase?

Polynucleotide phosphorylase, in addition to its role as an exonuclease, is also involved in the post-transcriptional addition of nucleotides to RNA in a template-independent manner: “Polynucleotide ...
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What is the effect of an acidic solution on hydrolytic enzymes?

I'm working on a school research project and my research question is "What is the effect of increasing concentrations of Acid X on hydrolytic enzymes, measured through the loss of mass of leaf ...
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Turnover number of the enzyme catalase

My textbook says that catalase is the fasting acting known mammalian enzyme and it can act on 40 million molecules of hydrogen peroxide per second. Does that mean that is acting on that number of ...
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Is the kinase domain of a protein kinase the same as the catalytic domain?

I am learning about protein kinases and I have read that the protein kinase domain is a structurally conserved protein domain containing the catalytic function of protein kinases. I am wondering ...
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Can a constitutively active kinase be highly regulated?

I am studying the protein kinase GSK3 and I am learning about the regulation of its activity. Many journal papers that I have read have stated that GSK3 is unique because it is a constitutively active ...
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Do phagocytes need antibodies to be able to engulf pathogens (to function)?

I recently saw a question about monoclonal antibodies, that are specific to a certain virus, being split (into their constant and variable regions via an enzyme), and the question asked whether some ...
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Enzyme inhibitor leads to higher turnover rate?

I'm currently working on a project where I have to deal with enzyme inhibition. The purified enzyme shows a good substrate turnover. When I try to inhibit it with different inhibitors described in ...
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Does Invertase catalyse the hydrolysis of other sugars other than sucrose?

I recently did a lab where we tested out the substrate specificity of Invertase on different types of sugars such as sugar alcohols and disaccharides, measured by the absorbance of red using a ...
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How do enzymes not change the overall energy change of the reaction they're catalysing if they lower the activation energy?

Based on the Induced-Fit model of enzyme action, enzymes catalyse a reaction by lowering the activation energy of a single forward reaction over and over. But I read that enzymes don't change the ...
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Why are many skin depigmenting agents toxic to the body?

Coming from a developing country, I know many people who regularly use these creams to lighten their skin and some of them have developed liver and kidney problems as a result. I know that many ...
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Do carboxylesterases, arylesterases and acylesterases count to the enzyme class of lipases? [duplicate]

I am currently examining the acyl transfer catalysis activity of several enzymes that I was told are all lipases. Through reading a couple of papers including these enzymes I found out that all of ...
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Basis of enzyme nomenclature — pyruvate dehydrogenase

In the formation of AcetylCoA from pyruvate, why is the enzyme called “pyruvate dehydrogenase (complex)” when it involves the decarboxylation of pyruvate or the replacement of a carbonyl group by ...
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Which enzymes use ATP?

It is well known that there are many enzymes which use ATP in their function, and any enzyme that work against an energy gradient need to have that energy supplied from somewhere, but just as well ...
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Are there ribozymes that cut double strands

the header already says: Are there any ribozymes known that cut double strands? A kind of ribozyme equivalent to the Ribonuclease III. With cut, I mean that the backbone of both strands, forming the ...
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What is the "GTP activator protein" that activates GTP-cyclohydrolase-1?

From GTP-cyclohydrolase deficiency responsive to sapropterin and 5-HTP supplementation: relief of treatment-refractory depression and suicidal behaviour (BMJ Case Reports, 2011) The metabolic profile ...
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ATP Synthase EC number

Why ATP synthase EC number is 7(Translocase)? My textbook says it's a hydrolase but when i checked its EC number it was changed to 7. And also ATPase(adensointriphosphatase) page that was previously ...
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Will Saliva make food go bad

My mom was telling me that if I put the unfinished bowl of milk and cereal back to the fridge, the saliva that has been stuck to the spoon gets passed to the milk. The saliva in milk will make milk go ...
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Alkaline Phosphatase and Ligase Protocol for Cloning

In the image the circular molecule is a restricted vector and the linear red molecule is a DNA insert. I found this protocol in my lessons notes, but I don't understand how it is possible that ligase ...
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Structure and reactions of the cofactors of oxidoreductases such as ferredoxin

I have seen the word flavoprotein being used in place of ferredoxin in few places and vice-versa. I have not found any source that mentions them both together and explains the relation between them. ...
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Calvin cycle- combining three "turns"

In the common Calvin cycle diagram, it is commonly stated that "three cycles are combined to show the production of 1 molecule of G3P". How does the G3P molecule escape from this cycle in ...
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Why do some enzymes have giant structures around the active site?

As a part of my inorganic chem. course (it's a required course at my college), we have a module called Introduction to Bioinorganic Chemistry. There, the prof. showed examples of enzymes like ...
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Why can't C1r cleave C4 proteins?

I am researching the complement system, and have ran into something I'm not really sure about. In the past, the C1r2s2 complex was thought to be an 8-like structure tucked inside C1q's collagenous ...
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Does Topiramate work by supplanting Pyridoxal phosphate in enzymes?

I have seen it said that the precise mechanism of action of migraine medicine Topiramate is not known. But I certainly see a resemblance between that molecule and PLP (Pyridoxal phosphate, the ...
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Lower optimum temperature of plant Catalase

Most resources give an optimum temperature of 35° C for Catalase. after performing the AP Catalase enzyme lab in school, using blended potatoes, our results gave a greater reaction rate at a room ...
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Why is this oxoglutarate dehydrogenase and not oxoglutarate decarboxylase?

I was looking at the oxoglutarate dehydrogenase complex and saw the reaction mechanism for its E1-TPP mechanism, which results in the formation of a stabilized carbanion intermediate. The mechanism ...
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Meaning of some unit of measurement of kinase activity

I need help knowing what $cpm \times 10^3$ means in Figure 4(C) of this paper (https://www.sciencedirect.com/science/article/pii/S0022202X15323149#f0010). It appears to be a unit of kinase activity.
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What does it mean for an enzyme to be "constitutively partially active"?

I am reading a paper* about the link between the enzyme GSK3 and autism, and I have come across the following statement: Unlike many kinases that require a signal to be activated, GSK3 is ...
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AMPK, PAN-AMPK, western blot

What does it mean by adding PAN before the AMPK. I am trying to do a western blot assay on AMPK and I am confused by PAN-AMPK, AMPK. does it mean pancreases? Is pan-ampk the total ampk?
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What changes do ants make to the soil they use for building ant hills

I live in South India ,and among the many species of ants in and around our house, some of them except the weaver ants build the typical small ant hills in the garden. I have examined the coarse sand ...
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What is "KK1 enzyme"?

In the book "The Kaizen Way" by Robert Maurer, I've read the following: When we’re sitting, our muscles go into a form of hibernation, causing our bodies to shut down the enzyme (called KK1)...
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What is the function of human Trypsin Inhibitor if trypsin is secreted in the inactive form of Trypsinogen? [closed]

I was reading about pancreatic digestive enzymes in a Textbook of Medical Physiology and I came across Trypsin Inhibitor. The text stated that: It is important that the proteolytic enzymes of the ...
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Can Mung Bean Nuclease only digest a ssDNA 5' overhang?

Can Mung Bean Nuclease only digest a ssDNA 5' overhang, if the double-stranded region of DNA (20bp) is A-T rich at the ends? Does this enzyme degrade 5' overhang (5bp or 30 bp) with 100% efficiency?
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How can cane sugar sucrose be different from beet sugar in regard to carbon-13 content?

According to an article in SCIENZA IN CUCINA, by Dario Bressanini, le Scienze Blog content of $^{13}C$ differs in sucrose in beet sugar compared to cane sugar. What is this due to? Are there any ...
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Low-tech or low-cost technique for quantitative estimation in enzymology

If an accurate measurement of enzymologic quantities is needed, then following established methods in the field is necessary. However, it is sometime of great usefulness to ballpark a value before ...
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How do organophosphates affect kidney function?

Many organophosphates, besides inhibiting acetylcholinesterase, can also permanently inhibit the enzyme neuropathy target esterase, leading to nerve damage. NTE also happens to be found in the kidneys,...
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Is there an enzyme that functions without being associated with a complex?

I'm looking for an enzyme that does not function as part of a complex in its active state. Preferably it also is not part of a kinase or other kind of activating cascade as well though I would ...
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What is the best way to find which domains in a list of InterPro IDs are catalytic?

What is the best way to find which domains in a list of InterPro IDs are catalytic? (In this case, we are looking at human enzymes and their domains' InterPro IDs.) Thanks in advance! Setz
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How to produce and isolate an enzyme? [closed]

I have recently learned that one of the best ways to isolate a protein in industry is via Chromatography. What are other ways enzymes are isolated in industry? Are there other ways?
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Finding total concentration of enzymes

Sorry if my question is very basic for biology majors because I am not. I am trying to build a mathematical model of a particular pathway using systems of differential equations and in order to reduce ...
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Activated carrier molecules and their relationship to enzymes

I am reading Molecular Biology of the Cell, and one thing I don't quite get is the difference between an enzyme and an activated carrier molecule. I understand that enzymes lower the activation energy ...
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Regarding the role of enzymes

Textbooks commonly state that the role of enzymes is to speed up a chemical rxn by lowering its activation energy. However, I'm unsure what enzymes like helicase, DNA/RNA polymerase, and restriction ...
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Can plants break down cellulose for energy?

I know humans and other animals start using their own proteins as food when starving. This made me wonder if a plant that is deprived of sunlight, after using up its sugar reserves and other carbs, ...
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Histone Deacetylase Inhibition

So I am trying to brush up on my knowledge of HATs and HDACs. I am reading the just the 1st paragraph of the background of this study I remember learning that HATs turn things on on, and HDACs turn ...
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Are there any small peptides with protease activity?

I'm looking for a very small protease to base an engineered protein on. I did a search for "peptides with protease activity" but all the results seem to be as peptides to be used as protease ...
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Why would Aspergillus Oryzae produce lactase when no lactose is present?

Studies [1] have shown that lactase is produced by A. oryzae when grown on wheat bran and spent beer grains. Why would A. oryzae produce lactase when these substrates have no lactose? In [1], it's ...
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Is there any current knowledge of how DNA polymerase is "motivated" to perform error corrections during transcription?

I was trying to understand the process of how polymerase performs error corrections on DNA. Every paper on this topic mentions what happens during the process, but there's no mention of how it happens....

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