Poly (vinyl alcohol) with pendent styrylpyridinium groups (SbQ) is insolubilized by photoirradiation. An association takes place in SbQ groups. The association of polymer chains becomes marked with increasing the number of SbQ groups. Mainly intermolecular crosslinks were formed. Transparent and homogeneous macrogels consisting of several intermolecular crosslinks are obtained.The proportion of the free water to the bound water in PVA-SbQ gels was 3.3-2.9 despite of the large change in conversion of photodimerization of SbQ groups, x=0.27-0.58. The water uptake after swelling of the gels in water increased 6-27 times compared to the original weight at pH=7. The higher the degree of photocrosslinking, the lower was the degree of swelling. The water diffusion coefficients, D , were (2.2-5.8)xlO-~cm2s-~ for a 88% saponified PVA with 1.3 mol% SbQ groups. The volume of the gel increased discontinuously about 10-fold for the 99% saponified PVA with 0.096 mol% SbQ and 51% water (49% acetone). The acetone concentration at the transition decreased with increasing the degree of saponification of the PVA.-Poster presented at the "
D-alpha-Hydroxyglutarate dehydrogenase of R. rubrum grown anaerobically in the light was partially purified and some properties were investigated. 1. The enzyme catalyze stoichiometrically the dehydrogenation reaction of D-alpha-hydroxyglutarate into alpha-oxoglutarate, coupled with the reduction of 2, 6-dichlorophenolindophenol. 2. Cytochrome c2, cytochrome c, and ferricyanide are effective as electron acceptors with the crude enzyme but not with the purified one, whereas NAD+ and NADP+ are completely ineffective. The enzyme is thought to play a role in the electron transport system of the organism. 3. D-alpha-Hydroxyglutarate is virtually the sole substrate for the enzyme. The apparent activity against L-alpha-hydroxyglutarate is presumed to be due to contamination of the L-isomer sample with the D-isomer. The enzyme shows barely detectable activity against both isomers of malate and virtually no activity against DL-lactate and glycolate. 4. Both isomers of malate and oxalate, which are presumably substrate analogues, inhibit the enzyme activity. 5. The enzyme is not an inducible enzyme but rather is a constitutive one for R. rubrum, unlike from the enzyme of Pseudomonas putida which is an inducible enzyme for the catabolism of lysine.
The investigation of the reactions of urea and its methyl derivatives with formaldehyde elucidated the formation pathway of 3,5-bis(methoxymethyl)perhydro-1,3,5-oxadiazin-4-one. 1) The addition of formaldehyde to urea became increasingly difficult according to the increase of the number of added formaldehyde molecules, probably because of the steric hindrance of the hydroxymethyl groups. 2) 3,5-Bis(methoxymethyl)perhydro-1,3,5-oxadiazin-4-one was concluded to be derived from urea via tris(hydroxymethyl)urea and 3-(hydroxymethyl)perhydro-1,3,5-oxadiazin-4-one but not via tetrakis(hydroxymethyl)urea or perhydro-1,3,5-oxadiazin-4-one.
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