I did a little research about possible connection between amygdalin and iodine and this is what I found:
More about lactoperoxidase system and iodide:
And another article on the same subject:
About thiocyanate (SCN):
Smokers can have more thiocyanate than non-smokers. Perhaps this is a reason why smoking is good against bacteria and viruses?
But this is also interesting:
But how do people get thiocyanate from smoking? Well, just like with bitter apricot kernels, from cyanide!
Impact of cyanogen iodide in killing of Escherichia coli by the lactoperoxidase-hydrogen peroxide-(pseudo)halide system
In the presence of hydrogen peroxide, the heme protein lactoperoxidase is able to oxidize thiocyanate and iodide to hypothiocyanite, reactive iodine species, and the inter(pseudo)halogen cyanogen iodide. The killing efficiency of these oxidants and of the lactoperoxidase-H2O2-SCN−/I− system was investigated on the bioluminescent Escherichia coli K12 strain that allows time-resolved determination of cell viability. Among the tested oxidants, cyanogen iodide was most efficient in killing E. coli, followed by reactive iodine species and hypothiocyanite. Thereby, the killing activity of the LPO-H2O2-SCN−/I− system was greatly enhanced in comparison to the sole application of iodide when I− was applied in two- to twenty-fold excess over SCN−. Further evidence for the contribution of cyanogen iodide in killing of E. coli was obtained by applying methionine. This amino acid disturbed the killing of E. coli mediated by reactive iodine species (partial inhibition) and cyanogen iodide (total inhibition), but not by hypothiocyanite. Changes in luminescence of E. coli cells correlate with measurements of colony forming units after incubation of cells with the LPO-H2O2-SCN−/I− system or with cyanogen iodide. Taken together, these results are important for the future optimization of the use of lactoperoxidase in biotechnological applications.
https://www.ncbi.nlm.nih.gov/pubmed/27629563
More about lactoperoxidase system and iodide:
The lactoperoxidase (LP) system is a natural antimicrobial system, the use of which has been suggested as a preservative in foods and pharmaceuticals. The effect of adding iodide to the LP system, the chemical stability and the change in antimicrobial effectiveness during storage was studied. Addition of iodide with thiocyanate increased the fungicidal and bactericidal effect against Candida albicans, Escherichia coli and Staphylococcus aureus. (...)
LP itself has no antimicrobial activity, but with H2O2 and thiocyanate ion (SCN–) it forms a natural antimicrobial system, the LP system. LP catalyses by means of H2O2 the oxidation of thiocyanate, forming hypothiocyanite, which has bacteriostatic activity ( Thomas et al. 1994 ). (...)
Gram-negative bacteria are more difficult to kill and inhibition is more dependent on temperature (between 5 and 20 °C) and pH (5·5–7), but iodide (I–) promotes killing independent of these factors. Also, fungi are killed in LP system with I– as the electron donor ( Lehrer 1969).
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2672.2000.01098.x/full
And another article on the same subject:
Biological Activity of Hypothiocyanite
Biological activity of hypothiocyanite on bacteria and possible defense mechanism of the bacteria. Reversible inhibition is observed in that (i) hypothiocyanite is not reactive against all thiols and (ii) if hypothiocyanite is removed or diluted, the pathogen recovers. Irreversible inhibition is linked to (i) long period of incubation, (ii) the bacterial species, and (iii) hypothiocyanite concentration.
Biological Action of Oxidized Iodide
Biological activity of hypoiodite or iodine on bacteria. Irreversible inhibition is observed and could be linked to (i) oxidation of thiol groups, NAD(P)H, and thioether groups, (ii) high reactivity of HOI/I2 against thiol and reduced nicotinamide nucleotides, and (iii) the incorporation of iodide in tyrosine residue of protein (iodination of protein).
The biological action of oxidized iodide (Figure 9) is similar to that of hypothiocyanite but differs in that (i) the reactivity of oxidized iodide is complete against thiol group and (ii) cells did not recover after removing of oxidized iodide [59].
Due to the cofactor role of I−, inhibition of respiration in Escherichia coli in the presence of LPO, H2O2, and I− is complete with only 10 μM NaI, whereas 100 μM of solely I2 is necessary to obtain complete inhibition. This is directly related to the oxidation of sulfhydryls, not to the percentage of iodine incorporation [92, 93].
E. coli seems to be more sensitive if the bacteria are incubated together with the entire system (enzyme, H2O2, and iodide) rather than adding several minutes after mixing the enzyme with its substrates. This could be linked to the formation of an unstable reactive intermediate [52].
The activity of the I− peroxidase system is more effective against E. coli than the SCN− system, in that lower I− concentrations are necessary, all sulfhydryls are oxidized, and cells do not recover even if the amount of I2 is not sufficient to oxidize all SH groups [59, 80].
https://www.hindawi.com/journals/er/2014/517164/
About thiocyanate (SCN):
SCN enters the body from the diet (such as cruciferous vegetables) [5] or is synthesized from cyanide by sulfurtransferase enzymes including mitochondrial rhodanese and cytosolic mercaptopyruvate sulfurtransferase [6].
The ubiquity of cyanogens in plant matter make it the most obvious dietary source of SCN and provide a rationale for the distribution of rhodanese activity across species, particularly ruminants where some segments of the alimentary tract may exceed the liver in sulfurtransferase activity [8].
Extracellular fluids are abundant sources of SCN (Table 1). Plasma values of SCN typically range between 5 and 50 μM in human non-smokers [11,12] and much higher in smokers [13].
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983948/
Thiocyanate is known to be an important part in the biosynthesis of hypothiocyanite by a lactoperoxidase. Thus the complete absence of thiocyanate or reducted thiocyanate in the human body, (e.g., cystic fibrosis) is damaging to the human host defense system. Thiocyanate is a potent competitive inhibitor of the thyroid sodium-iodide symporter.
http://www.liquisearch.com/thiocyanate/biological_chemistry_of_thiocyanate_in_medicine
Thiocyanate is produced by the reaction of elemental sulfur or thiosulfate with cyanide:
8 CN− + S8 → 8 SCN−
CN− + S2O32− → SCN− + SO32−
The second reaction is catalyzed by the enzyme sulfotransferase known as rhodanase and may be relevant to detoxification of cyanide in the body.
http://www.liquisearch.com/thiocyanate
Smokers can have more thiocyanate than non-smokers. Perhaps this is a reason why smoking is good against bacteria and viruses?
In a Norwegian health study involving 25,300 persons the mean serum thiocyanate level in non-smokers was 33.9 mumol/l for males and 33.5 mumol/l for females. In moderate smokers (five to nine cigarettes per day) the mean level was 59.6 mumol/l for males and 70.9 mumol/l for females. In heavy smokers (greater than 25 cigarettes per day) the mean level was 87.3 mumol/l in males and 99.7 mumol/l in females.
https://www.ncbi.nlm.nih.gov/pubmed/3715377
But this is also interesting:
The range of the individual thiocyanate level was great both in non-smokers and in smokers, resulting in a large overlap. Serum thiocyanate can therefore not distinguish all non-smokers from all smokers.
But how do people get thiocyanate from smoking? Well, just like with bitter apricot kernels, from cyanide!
Tobacco smoke contains considerable amounts of cyanide, which is generated in the burning zone of the tobacco from proteins and nitrate at high temperatures. The amount of cyanide generated from a single cigarette may differ widely depending on the smoking conditions (Scherer, 2006). The cyanide is highly toxic but is rapidly detoxified in the liver of the smoker to thiocyanate by a sulfation process.
Serum concentrations of thiocyanate are two to three times higher in smokers than in nonsmokers. In populations not exposed to excessive amounts of thiocyanate from diet or industrial environmental pollution, thiocyanate concentrations in serum can be used to identify and quantify tobacco smoking (Scherer, 2006; Butts et al., 1974).
In a Belgian study the levels of thiocyanate in serum from heavy smokers were not much different from the serum concentrations found in people in Central Africa with a high intake of cyanide from only partly detoxified cassava (Delange et 1980). Thus, heavy smoking may be as important in the generation of thiocyanate as is severe dietary intake of cyanide, and serum levels of thiocyanate in smokers overlap the levels found in people exposed to severe industrial pollution.
https://books.google.rs/books?id=7v7g5XoCQQwC&pg=PA275&lpg=PA275#v=onepage&q&f=false
