New answers tagged biochemistry
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Note that branching is not unheard of, for instance glutathione is an abundant short branched peptide formed by condensation of the carboxylic group on a glutamic acid side chain to the main chain amino group of a cysteine aminoacid. This requires a dedicated enzyme both for synthesis (glutamate cysteine ligase) and degradation of the gamma peptide bond. ...
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An aldol is a $\beta$-hydroxy ketone or aldehyde, and is the product of an aldol addition.
The enzyme that cleaves the bond formed (red) is known as an aldolase. The transaldolase reaction begins by aldol cleavage that is, cleavage of the bond in red.
Transketolase on the other hand simply cleaves off the ketone group from the substrate. It does not ...
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Proteins are built from monomers with only two linking groups
The monomers that make up proteins join in very specific ways. The general structure is:
where R can be a variety of possible groups. To form a protein the monomers join when the amino group reacts with the carboxylic acid group. this gives a product with a specific orientation and which still ...
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All particles are constantly moving randomly due to their kinetic energy, and are thus constantly colliding into each other and the walls of their container (if any).
Particles in gases move rapidly and randomly and are spaced far apart, particles in liquids slide slowly over each other, and particles in solid vibrate around a fixed position.
Hence, ...
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A remarkable aspect of the Ramachandran plots is that the implementation of a hard-sphere potential with flexibility limited to the two backbone dihedrals proved sufficient to largely explain the conformational range sampled by real polypeptides. Take for instance the following map from a seminal article by Ramachandran (from Ref. 1; dashed line encloses the ...
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The illustration is likely taken from a later edition of Baum's Introduction to organic and biological chemistry.
The first edition [1, p. 292] presents nearly identical illustration under a different number alongside with a note that the image was adapted from Bennett's Graphic Biochemistry [2]:
Unfortunately, at the moment (2020-10-16) [1] is available on ...
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You have calculated correctly for parts $\bf{a}$ and $\bf{b}$. However, to answer part $\bf{c}$, you need to use the given plot, the interception and slope of which can be calculated as follows:
The slope is $\tan \alpha = - \frac{1}{K_d}$:
$$\tan \alpha = \frac{1-0.2}{0.1-0.8} = -1.14 \ \Rightarrow \ \therefore \ \frac{1}{K_d} = 1.14$$
According to the ...
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This would be a tail-to-tail connectivity, which has not been observed so far according to this source:
Structurally, for ranunculins A-D (Fig. 6), their potential 6-hydroxymethyls of 3-deoxyglucosones (3-DG) connected with another 6-hydroxymethyl group of sugars through a 6,6′-ether-bond (tail to tail ether-bond)10,11,12,13,14,15. In nature, such types of ...
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The extra information from the ingredient list helps suggest some reactions that may be occurring.
The antibacterial foaming soap contains four detergents (not salts of fatty acids), probably totaling 10-15% by weight of the product. The antibacterial action is provided by the benzalkonium chloride at 0.13%. The label tells you to avoid contact with the eyes,...
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The soap solutions were originally transparent. An interesting experiment, if you still have some of the original soaps, is to shine a light thru the solutions and look for a Tyndall effect:
The light source is on the far right, out of the picture. The beaker on the right shows light scattering from particles comparable in size to the wavelength of light ...
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When the ratio of conjugate base concenteration to conjugate acid concenteration is more than 1000 , we say that the dissociation of acid is complete.
According to Henderson–Hasselbalch equation the ratio of conjugate base concenteration to conjugate acid concenteration gets more than 1000 , when PH-PKa is more than 3.
For strong acids, this ratio is more ...
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ATP has two high energy bonds which are phosphoanhydride bonds. Both bonds release the same amount of energy. Therefore, when ATP converts to ADP, breaks one phosphoanhydride bond, and releases -30.5 kJ/mol. When the 2nd bond is broken in ADP releases -30.5 kJ/mol because it is the same phosphoanhydride bond. However, AMP has only a phosphate ester bond ...
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It is like the problem of the key and the lock. If you put the good key in a given lock, it will go all right.It will open the lock. But if you make up a new key which is the image of the original key, it will not open the lock.
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