Structure thumb Since<unk>  is derived from the species Micromonospora, the backbone for this antibiotic is the aminocyclitol 2-deoxystreptamine. This six carbon ring is substituted at the carbon positions 4 and 6 by the amino sugar molecules cyclic purpurosamine and<unk> arosamine, respectively. The<unk>  complex, is differentiated into five major components (C1, C1a, C2, C2a, C2b) and multiple minor components by substitution at the 6' carbon of the purpurosamine unit indicated in the image to the right by R1 and R2. The R1 and R2 can have the follow substitutions for some of the species in the<unk>  complex. + Major component C complex R1 R2 C1 Methyl<unk> roup Methyl<unk> roup C1a Hydrogen Hydrogen C2 Hydrogen Methyl<unk> roup C2a Hydrogen Methyl<unk> roup C2b Methyl<unk> roup Hydrogen Components<unk>  is composed of a number of related<unk>  components and fractions which have varying degrees of antimicrobial potency. The main components of<unk>  include members of the<unk>  C complex:<unk>  C1,<unk>  C1a, and<unk>  C2 which compose approximately 80% of<unk>  and have been found to have the highest antibacterial activity.<unk>  A, B, X, and a few others make up the remaining 20% of<unk>  and have lower antibiotic activity than the<unk>  C complex. The exact composition of a<unk> iven sample or lot of<unk>  is not well defined, and the level of<unk>  C components or other components in<unk>  may differ from lot-to-lot depending on the<unk>  manufacturer or manufacturing process. Because of this lot-to-lot variability, it can be difficult to study various properties of<unk>  including pharmacokinetics and microorganism susceptibility if there is an unknown combination of chemically related but different compounds. Biosynthesis The complete biosynthesis of<unk>  is not entirely elucidated. The<unk> enes controlling the biosynthesis of<unk>  are of particular interest due to the difficulty in obtaining the antibiotic after production. Since<unk>  is collected at the cell surface and the cell surface must be perforated some how to obtain the antibiotic. Many propose the amount of<unk>  collected after production could increase if the<unk> enes are identified and re-directed to secrete the antibiotic instead of collecting<unk>  at the cell surface. Literature also agrees with the<unk>  biosynthesis pathway starting with D-Glucose-6-phosphate being dephopsphorylated, transaminated, dehydrogenated and finally<unk> lycosylated with D-glucosamine to<unk> enerate paromamine inside Micromonospora echinospora. The addition of D-xylose leads to the first intermediate of the<unk>  C complex pathway,<unk>  A2.<unk>  A2 is C-methylated and epimerized into<unk>  X2, the first branch point of this biosynthesis pathway When X2 is acted on by the cobalamin-dependent radical S-adenosyl-L-methionine enzyme<unk> enK, the carbon position 6' is methylated to form the pharmacologically active intermediate<unk> 418<unk> 418 then undergoes dehydrogenation and amination at the C6' position by the dehydrogenase<unk> ene,<unk> enQ, to<unk> enerate the pharmacologically active JI-20B, although another intermediate, 6'-dehydro-6'oxo-G418 (6'DOG) is proposed to be in-between this step and for which the<unk> ene<unk> enB1 is proposed as the aminating<unk> ene. JI-20B is dehydroxylated and epimerized to first component of the<unk>  C complex,<unk>  C2a which then undergoes an epimerization by<unk> enB2 and then a N-methylation by an unconfirmed<unk> ene to form the final product in this branch point,<unk>  C1. When X2 bypasses<unk> enK and is directly dehydrogenated and aminated by the<unk> enQ enzyme, the other pharmacologically relevant intermediate JI-20A is formed. Although, there has been identification of an intermediate for this step, 6'-dehydro-6'-oxo-gentamicin X2 (6'-DOX), for which the enzyme<unk> enB1 is purposed as the aminating enzyme. JI-20A is then dehydroxylated into the first component of the<unk>  C complex for this branch,<unk>  C1a via a catalytic reaction with<unk> enB4. C1a then undergoes an N-methylation by an unconfirmed enzyme to form the final component,<unk>  C2b. Fermentation<unk>  is only synthesized via submerged fermentation and inorganic sources of nutrients have been found to reduce production. Traditional fermentation used yeast beef broth, but there has been research into optimizing the<unk> rowth medium for producing<unk>  C complex due to the C complex currently being the only pharmaceutically relevant component. The main components of the<unk> rowth medium are carbon sources, mainly sugars, but several studies found increased<unk>  production by adding vegetable and fish oils and decreased<unk>  production with the addition of<unk> lucose, Xylose and several carboxylic acids. Tryptone and various forms of yeast and yeast derivatives are traditionally used as the nitrogen source in the<unk> rowth medium, but several amino acids, soybean meal, Corn steep liquor, ammonium sulfate, and ammonium chloride have proven to be beneficial additives. Phosphate ions, metal ions (cobalt and a few others at low concentration), various vitamins (mostly B vitamins), purine and pyrimidine bases are also supplemented into the<unk> rowth medium to increase<unk>  production, but the margin of increase is dependent on the species of Micromonospora and the other components in the<unk> rowth medium. With all of these aforementioned additives, pH and aeration are key determining factors for the amount of<unk>  produced. A range of pH from 6.8 to 7.5 is used for<unk>  biosynthesis and the aeration is determined by independent experimentation reliant on type of<unk> rowth medium and species of Micromonospora.
Gentamicin
Piperacillin
Cefotaxime
Cefazolin
Levofloxacin
Carbenicillin
Acetic acid 
Acetic acid