Oleandomycin

Key takeaways

Oleandomycin belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Oleandomycin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Oleandomycin from memory before moving on to harder problems.

Reference excerpt

Oleandomycin is a macrolide antibiotic. It is synthesized from strains of Streptomyces antibioticus. It is weaker than erythromycin. It used to be sold under the brand name Sigmamycine, combined with tetracycline, and made by the company Rosa-Phytopharma in France.

Medical uses Oleandomycin inhibits the bacteria responsible for upper respiratory tract infections. Its spectrum of activity includes bacteria in the Staphylococcus and Enterococcus genera. The MIC for oleandomycin is 0.3-3 μg/mL for Staphylococcus aureus. Oleandomycin is approved as a veterinary antibiotic in some countries. It has been approved as a swine and poultry antibiotic in the United States. However, it is currently only approved in the United States for production uses.

Pharmacology

Mechanism of action Oleandomycin is a bacteriostatic agent. Like erythromycin, oleandomycin binds to the 50s subunit of bacterial ribosomes, inhibiting the completion of proteins vital to survival and replication. It interferes with translational activity but also with 50s subunit formation. However, unlike erythromycin and its effective synthetic derivatives, it lacks a 12-hydroxyl group and a 3-methoxy group. This change in structure may adversely affect its interactions with 50S structures and explain why it is a less powerful antibiotic.

Relative strength Oleandomycin is far less effective than erythromycin in bacterial minimum inhibitory concentration tests involving staphylococci or enterococci. However, macrolide antibiotics can accumulate in organs or cells and this effect can prolong the bioactivity of this category of antibiotics even if its concentration in plasma is below what is considered capable of a therapeutic effect.

Chemistry

Polyketide biosynthesis

The oleandomycin synthase (OLES) follows the module structure of a type I synthase. The polyketide chain is bound through thioester linkages to the S-H groups of the ACP and KS domains

The gene cluster OLES1 codes for modules 0-2, module 0 containing an acetyl-CoA starter unit and all remaining moduless carrying a methyl malonyl-CoA elongation unit attached to its keto synthase unit. OLES2 codes for modules 3 and 4. Module 3 is notable for potentially carrying a redox-inactive ketoreductase that is responsible for retaining the unreduced carbonyl adjacent to carbon 8. OLES3 codes for modules 5 and 6. The amino acid sequence similarities between OLES and 6-Deoxyerythronolide B synthase (erythromycin precursor synthase) show only a 45% common identity. Note that unlike in the erythromycin precursor synthase, there is a KS in the loading domain of OLES.

Post-PKS modifications

The genes OleG1 and G2 are responsible for the glycosyltransferases that attach oleandomycin's characteristic sugars to the macrolide. These sugars are derived from TDP-glucose. OLEG1 transfers dTDP-D-desoamine and OleG2 transfers D-TDP-L-oleandrose to the macrolide ring. The epoxidation that occurs afterwards is from the enzyme encoded by OleP, which could be homologous with a P450 enzyme. The method by which OleP epoxidates is suspected to be a dihydroxylation followed by the conversion of a hydroxyl group into a phosphate group that then leaves via a nucleophilic ring closure by the other hydroxyl group.

History Oleandomycin was first discovered as a product of the bacterium Streptomyces antibioticus in 1954 by Dr. Sobin, English, and Celmer. In 1960, Hochstein successfully managed to determine the structure of oleandomycin. This macrolide was discovered at around the same time as its relatives erythromycin and spiramycin.

Sigmamycine combination drug Public interest in oleandomycin peaked when Pfizer introduced the combination drug Sigmamycine into the market in 1956. Sigmamycine was a combination drug of oleandomycin and tetracycline that was supported by a major marketing campaign. It was in fact claimed that a 2:1 mixture of tetracycline and oleandomycin had a synergistic effect on staphylococci. It was also claimed that the mixture would be effective on organisms that are mostly resistant to tetracycline or oleandomycin alone. Both of these claims were refuted by findings such as those by Lawrence P. Garrod that could find no evidence that such claims were properly substantiated. By the early 1970s, Pfizer's combination drugs were withdrawn from the market.

Society and culture

Brand names Mastalone – Oleandomycin, oxatetracycline, neomycin – Zoetis Australia and Pfizer Animal Health Mastiguard – Oleandomycin, oxatetracycline – Stockguard Animal Health Formerly sold as Sigmamycine by Pfizer (Oleandomycin + Tetracycline + Vitamin C)

References

Illustrations

Worked examples

Example 1 — a first encounter with Oleandomycin

Start with the simplest possible case. Write down what Oleandomycin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Oleandomycin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Oleandomycin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Oleandomycin

In research: Oleandomycin appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Oleandomycin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Oleandomycin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dimethylamino compounds, Fourteen-membered rings, Macrolide antibiotics, so understanding it makes those chapters shorter.
In everyday life: Look for Oleandomycin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Oleandomycin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Oleandomycin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Oleandomycin out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Oleandomycin in simple terms?

Oleandomycin is a macrolide antibiotic. It is synthesized from strains of Streptomyces antibioticus.

Why does Oleandomycin matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Oleandomycin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Oleandomycin.