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  • Bacillus circulans var. alkalophilus  (1)
  • salicylaldehyde  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Acid-base chemistry of vitamin B6 compounds in methanol (1988)
    Springer
    The protein journal 7 (1988), S. 549-559 
    Details
    ISSN: 1573-4943
    Keywords: Pyridoxal ; pyridoxal 5′-phosphate ; salicylaldehyde ; mechanism of B6-vitamin-dependent enzymes ; acidity in organic solvents ; tautomerism ; protolytic equilibria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The enzymatic reactions involving pyridoxal 5′-phosphate (PLP) can be simulated in solutions; thus, this system forms a favorable model for understanding the requirements of the enzymatic catalysis. We have studied in methanol protonic equilibria of the imines formed between PLP or salicylaldehyde (SA) and various amino acids, using UV and NMR spectroscopy. A glass electrode and an operationalpH* scale were used to control acidity. The first protonation of the phosphate of PLP imines can be detected by UV spectroscopy withpK* at 10.8, proved by [31P]-NMR. The second protonation of phosphate (pK* at 4.8) is accompanied by increased hydrolysis of the imines. The imines of aspartate deviate from the imines of nondicarboxylic amino acids indicating that the β-carboxyl of aspartate is internally hydrogen-bonded. PLP-2-aminobutanol Schiff base does not show with [1H]-NMR atpH* 7 separate peaks for ketoenamine-enolimine tautomers even at -90°C, SA-phenylalanine shows an unidentified absorption at 350–380 nm. This was tentatively assigned a trans structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01024873
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  • 2
    Electronic Resource
    Electronic Resource
    Catabolic pathways of glucose in Bacillus circulans var. alkalophilus (1999)
    Springer
    Extremophiles 3 (1999), S. 269-276 
    Details
    ISSN: 1433-4909
    Keywords: Key words Alkaliphile ; Glucose metabolism ; Bacillus circulans var. alkalophilus ; Enzyme activities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enzymes and the metabolic pathways of glucose catabolism of Bacillus circulans var. alkalophilus were studied. The metabolism of the microbe was mixed acid fermentative yielding mainly acetic and formic acids as end products from glucose. It was estimated that B. circulans var. alkalophilus partitions 90%–93% of the carbon from glucose into the Embden-Meyerhof-Parnas (EMP) pathway and 7%–10% into the hexose monophosphate (HMP) and Entner-Doudoroff (ED) pathways. Rather low activities of glucose dehydrogenase and gluconokinase appeared in the early logarithmic and late stationary phases, whereas NADH oxidase was markedly high. This result can be explained by a demand to reduce NADH to NAD+ for the EMP pathway; when acetic and formic acids are produced, no NADH is regenerated to NAD+, which is required in the early steps of EMP and HMP pathways. A small percentage (1.6%–2.4%) of the total CO2 was formed from (6-C) of glucose, which means that the tricarboxylic acid cycle was functional but its contribution was insignificant. Large differences do not seem to exist between alkaliphilic and neutrophilic bacilli in the use of glucose pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007920050127
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