1
vote
0answers
43 views

amino acid containing branched side chain

Branched-chain amino acid are degraded by branched chain alpha-keto acid dehydrogenase complex. These amino acids aren't degraded in liver because of the absence of this enzyme(in liver).Why the ...
3
votes
1answer
19 views

bacterial cell wall degradation in humans

can human degrade the D-amino acid present in bacterial cell wall, I'm confused about it i have read somewhere that human can do so.If yes than why we need antibiotic to kill bacteria???If it is not ...
2
votes
1answer
32 views

Activity of glucokinase

From Solomon et al, 2013 ACC Synthetic biology and from this video : Here, there are 2 competing reactions for glucose - one with glk as enzyme and other with gdh as enzyme. In the graph, y axis ...
0
votes
2answers
40 views

Why is succinate dehydrogenase attached to the inner mitochondrial membrane?

Succinate dehydrogenase is attached to the inner mitochondrial membrane.All the other enzymes of the Krebs cycle are located in the matrix of mitochondria. What is the biochemical reason behind ...
1
vote
1answer
27 views

Correlating Ki values of pesticides to bacterial growth

Four pesticides P1 to P4 are reversible inhibitors of an enzyme E that is essential for the growth of a bacterium B. Their Ki values are given in the table below. Each of these four pesticides ...
1
vote
1answer
27 views

Correlating B-lactamase expression to absorbance

When penicillin-resistant bacteria are grown in liquid culture media, B -lactamase is secreted into the medium. The supernatant of such a medium can be assayed for B- lactamase activity. Culture ...
1
vote
1answer
68 views

Creative ways to deactivate alpha-amylase taken from fungi

I can deactivate $\alpha$-amylase in ways such as extreme temperature controls, pH controls of the solution it stays in, or adding salt to the solution. However, are there any other unique or ...
3
votes
3answers
118 views

Are there any methods to quantify H2O2 (hydrogen peroxide) which don't rely on horseradish peroxidase?

I can't use HRP since my substrates interfere with it and I need a real-time method because I want to measure kinetic parameters of some oxidases.
0
votes
1answer
45 views

Carotenoid biosynthesis in yeast

Does Budding Yeast Sacchromyces cerevisiae produces significant amount of carotenoids? Have anybody estimated the ratio of flux going in branches 1. Cholesterol synthesis(via squalene) 2. Coenzyme Q6 ...
4
votes
2answers
314 views

Why are enzyme-catalysed reactions slower at lower substrate concentration?

Suppose I'm using 200 nmoles of enzyme and 2 mmoles of substrate. The enzyme should be saturated but if I use 50 mmoles of substrate, the reaction will be faster. Why? I just can't get it! Even at ...
5
votes
1answer
82 views

Photosynthesis regulation

I read about the regulation of Calvin cycle by thioredoxin which activates key enzymes essentially by converting disulphide linkages on inactive enzymes into sulfhydryls. Another regulatory mechanism ...
2
votes
3answers
464 views

Michaelis-Menten Kinetics: Does measuring apparent Km and Vmax take into account competing reactions?

I am learning about why it is important to measure Km and Vmax for each experimental setup because measuring the "apparent" Km and Vmax includes enzyme inhibitions of which one might not be aware. ...
2
votes
1answer
58 views

Which Enzymes are Responsible for the Biodegradation of Noladin Ether?

Which enzymes degrade the CB1-specific endogenous cannabinoid 2-arachidonyl glyceryl ether? (Noladin ether)
2
votes
1answer
36 views

Which Enzymes are Responsible for the Biodegradation of Beta-endorphin?

Which enzymes are responsible for the biodegradation of the endogenous opioid peptide, beta-endorphin?
6
votes
1answer
294 views

$S_{0.5}$ vs $K_m$ values in enzyme kinetics

What is the difference between $S_{0.5}$ values and $K_m$ values in enzyme kinetics?
4
votes
1answer
102 views

Are there any websites offering graphs for the light absorption of different enzymes?

I have found graphs for the light absorption of water, haemoglobin, lipids, melanin, etc., but I am having a hard time finding graphs about enzymes. Are there any websites or other reference sources ...
5
votes
1answer
301 views

What are the units of enzyme activity?

I was looking at this graph of turnip peroxidase activity and I saw that they use units of 1/sec for enzyme activity. What does this unit intuitively represent and how is it calculated?
13
votes
2answers
762 views

Is the EC50 of an activating protein for an enzyme a good indicator for the binding affinity Kd?

We work with a membrane protein system where measuring the affinity between the enzyme and the upstream activating protein has been difficult, and when measured in detergent solution, it is almost 100 ...
6
votes
2answers
703 views

What is the correct model for enzyme-substrate complementarity?

This Wikibook shows both proposed models of enzyme-substrate complementarity, the Lock and Key model and the Induced Fit model. I've always been taught that the Induced Fit model is the proper one. ...
6
votes
1answer
164 views

Is there an enzyme for the transformation of the hydroxyl group?

I would like to know, is there any enzyme which does the transformation of hydroxyl group to any other functional group using the enzyme. The substrate is aromatic hydroxyl group. Product should not ...
17
votes
3answers
220 views

How crowded is the bacterial cell?

I was wondering what is the protein concentration in an E. coli cell. When studying enzyme kinetics and activity in vitro, I would argue that the substrate and enzyme concentrations resemble those in ...
10
votes
2answers
387 views

Why does cyanide inhibit CuZnSOD, but not MnSOD or FeSOD?

Different types of superoxide dismutase (SOD) contain different metal ions (Zn, Cu, Mn, Ni, or Fe), all of which allow them to catalyze one reaction, dismutation of superoxide anion, O2−. Cyanide can ...
13
votes
1answer
7k views

What effect has changing pH and salt concentration on protein complexes?

I'm struggling to find peer reviewed literature that explains the effect of changing the pH and the salt concentration on protein/protein complexes in solution. What effect does the pH and the salt ...
7
votes
2answers
427 views

How can I measure bacterial alkaline phosphatase activity?

I want to measure alkaline phosphatase activity using PNPP in my mutant bacteria strains, but all the protocols I found involve purification of the phosphatase (which I have no need of). Does anyone ...