Disease relevance of propylene glycol

• Salmonella spp., but not E. coli, have acquired by horizontal transfer the ability to synthesize B12 and degrade propanediol [1].
• A new isolation procedure for propanediol dehydratase increases by a factor of about 16 the yield of enzyme obtainable from Klebsiella pneumoniae; the enzyme thus isolated has a specific activity of 95 +/- 4 units/mg [2].
• Analyses showed that the S. typhimurium propanediol dehydratase was related to coenzyme B12-dependent glycerol dehydratases from Citrobacter freundii and Klebsiella pneumoniae [3].
• MATERIAL AND METHODS: A total of 1408 human 2PN embryos were cryopreserved using a Planer Kryo 10 Series III freezing unit (TS Scientific, Perkasie, Pa) after dehydration/equilibration through Propanediol (Sigma Chemical, St. Louis, Mo) and sucrose [4].
• Human ovarian tissue was cryopreserved using propanediol and sucrose and grafted under the renal capsule of bilaterally oophorectomized severe combined immunodeficient (SCID) mice [5].

High impact information on propylene glycol

• The branch of enteric taxa from which Salmonella spp. and E. coli evolved appears to have lost the ability to synthesize B12 and the ability to use it in propanediol and glycerol degradation [1].
• The cyclization/cleavage of 3',5'-uridyluridine to form 2',3'-cyclic uridylic acid is very effectively catalyzed by Eu3+, and the cyclization/cleavage of the 1-p-nitrophenyl phosphate ester of propane-1,2-diol also shows strong metal ion catalysis by Eu3+, Tb3+, and Yb3+ [6].
• In this study we show that continued selection for aerobic growth on propanediol resulted in mutations in the oxidoreductase conferring increased resistance to MCO [7].
• Here we address the determinants of Ape AP endonuclease activity using duplex DNA substrates that contain synthetic analogs of AP sites: tetrahydrofuranyl (F), propanediol (P), ethanediol (E), or 2-(aminobutyl)-1,3-propanediol (Q) [8].
• In contrast, the specificity constant (kcat/Km) for E or P of Ape purified from HeLa cells was only 5-8-fold lower than for F [8].

Chemical compound and disease context of propylene glycol

• The enzyme propanediol oxidoreductase, which converts the lactaldehyde formed in the metabolism of fucose and rhamnose into propane-1,2-diol under anaerobic conditions, was investigated in Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium [9].
• The propanediol utilization (pdu) operon of Salmonella enterica serovar Typhimurium LT2 contains genes needed for the coenzyme B(12)-dependent catabolism of 1,2-propanediol [10].
• The FucO protein, a member of the group III "iron-activated" dehydrogenases, catalyzes the interconversion between L-lactaldehyde and L-1,2-propanediol in Escherichia coli [11].
• Disruption of the fucose pathway as a consequence of genetic adaptation to propanediol as a carbon source in Escherichia coli [12].
• Glycerol, ethylene glycol and propanediol elicit pimaricin biosynthesis in the PI-factor-defective strain Streptomyces natalensis npi287 and increase polyene production in several wild-type actinomycetes [13].

Biological context of propylene glycol

• Expression of both operons is induced by propanediol and globally controlled by the ArcA and Crp systems [14].
• A new class of mutations, pocR, prevents induction of the cob/pdu regulon by either propanediol or glycerol and causes a Cob- Pdu- phenotype [15].
• The two parallel pathways, with their own permeases and enzymes encoded by two widely separated gene clusters, appear to share a single enzyme that catalyzes the formation of L-1,2-propanediol [16].
• A clone that expresses propanediol dehydratase activity was isolated from a Salmonella genomic library [3].
• Unexpectedly, the S. typhimurium propanediol dehydratase was found to be 98% identical in amino acid sequence to the Klebsiella oxytoca propanediol dehydratase; this is a much higher identity than expected, given the relationship between these organisms [3].

Anatomical context of propylene glycol

• The entry of glycerol into the hepatocytes is highly sensitive to inhibition by monoacetin and cytochalasin B, but not by DL-1,2-propanediol, erythritol, D-glucose, D-galactose, D-mannose, or D-fructose [17].
• Electrical stimulation of the lateral hypothalamic area (LHA) increased the excitability of these ANG II-sensitive SFO neurons (58% in the PG-treated animals and 52% in the EB-treated animals) [18].
• Twenty-eight subfornical organ (SFO) neurons in ovariectomized (OVX) female rats that were treated with propylene glycol (PG) vehicle and 26 SFO neurons in OVX female rats that were treated with estrogen benzoate (EB) were antidromically activated by electrical stimulation of the hypothalamic paraventricular nucleus (PVN) under urethane anesthesia [18].
• METHODS: Superovulated oocytes with cumulus cells were cryopreserved by slow freezing in propanediol combined with a rapid thawing protocol [19].
• Pronuclear zygotes (n = 233) from 101 patients were frozen using propanediol 21-35 h following egg collection [20].

Associations of propylene glycol with other chemical compounds

• Plasma concentrations of ornidazole and its two major hydroxylated metabolites, M1 (alpha-(chloromethyl)-2-hydroxymethyl-5-nitroimidazole-1-ethanol) and M4 (3-(2-methyl-5-nitroimidazole 1-yl) 1,2 propane diol), were measured by HPLC [21].
• The pdu operon encodes proteins for the catabolism of 1,2-propanediol; the nearby cob operon encodes enzymes for the biosynthesis of adenosyl-cobalamin (vitamin B12), a cofactor required for the use of propanediol [22].
• The enzyme has a pH optimum of 6.5 for the reduction of L-lactaldehyde and of 9.5 for the dehydrogenation of L-1,2-propanediol [23].
• Mutants that grow on L-1,2-propanediol as a carbon and energy source also depend on the ald gene product for the conversion of L-lactaldehyde to L-lactate [24].
• Selection for increased aerobic growth rate on propanediol results in the escalation of basal synthesis of the NAD+-linked oxidoreductase encoded by fucO, a member of the fuc regulon for the utilization of L-fucose [25].
• The amino acid prodrugs containing methoxy linker were the least stable while prodrugs containing propylene glycol linker were most stable [26].

Gene context of propylene glycol

• Mutants serially selected for aerobic growth on propanediol became constitutive in fucO and fucA [fucO(Con) fucA(Con)], but noninducible in fucPIK [fucPIK(Non)] [27].
• Mutations in two of these groups (pduC and pduD) eliminate propanediol dehydratase activity [28].
• Propanediol utilization genes (pdu) of Salmonella typhimurium: three genes for the propanediol dehydratase [3].
• A model for control of this regulon suggests that the PocR protein is a transcriptional activator of both the cob and pdu operons and that both glycerol and propanediol can individually serve as effectors of the PocR protein [15].
• Glycerol consumption was associated with the induction of (i) a glycerol dehydrogenase and a dihydroxyacetone kinase feeding glycerol into the central metabolism and (ii) an oxygen-sensitive glycerol dehydratase and an NAD-dependent 1,3-propanediol dehydrogenase involved in propanediol formation [29].

Analytical, diagnostic and therapeutic context of propylene glycol

• Complementation and expression studies with subclones constructed via PCR showed that three genes (pduCDE) are necessary and sufficient for propanediol dehydratase activity [3].
• Cryopreservation of 2-cell mouse embryos using propanediol did not cause zona hardening but induced a small and significant softening, as gauged by the time taken for zona dissolution (2181 +/- 167 versus 1864 +/- 82 s) [30].
• FTM (25 mg/kg) or vehicle (propanediol) was injected subcutaneously 30 minutes before the end of resuscitation [31].
• After cryoprotective treatment in the presence of propanediol, cortical polymerized actin was no longer visible within the egg and along junctional feet but filamentous actin was still present after treatment with dimethylsulphoxide [32].
• A total of 220 oocytes, obtained from volunteers who had undergone ovarian stimulation, were cryopreserved using a slow freeze-rapid thaw protocol with 1.5 M propanediol as the cryoprotectant [33].

References