Kinetik der Hexulose‐6‐phosphat‐Synthase methylotropher Bakterien <i>in vitro</i> und <i>in situ</i>

Babel, Wolfgang; Müller, Roland

doi:10.1002/jobm.19770170302

Cited by 16 publications

(9 citation statements)

References 26 publications

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“…Mechanisms which may be responsible for the generation of such "bumpy" curves are discussed elsewhere MULLER 1977, MULLER and. …”

Section: Resultsmentioning

confidence: 99%

“…The expressions of this regulatory behaviour are coniplex kinetic characteristics with the appearence of intermediary plateau regions. Such a feature could be demonstrated in all obligate and facultative methanol-utilizing bacteria, investigated by BABEL and MULLER, and for this reason it is assumed to be a general substratedependent feature of the HPS in bacteria of this type (BABEL and MULLER 1977,1978, MULLER and BABEL 1977.After the purification of the HPS from the facultative methylotrophic bacteriuni MB 58 (MULLER and BABEL 1978) it was possible to demonstrate that multiple and interconvertible enzyme forms are responsible for the generation of the plateau regions (MULLER 1978, MULLER andBABEL, 1979). The presence of HPS has been shown also in the facultative methylotroph Pseudomonas oleovorans after growth on methanol and methylaniine (LOGINOVA and TROTSENKO 1977).…”

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confidence: 93%

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Kinetic properties of the purified 3‐hexulosephosphate synthase from Pseudomonas oleovorans

Müller

Соколов

1979

J of Basic Microbiology

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The kinetic characteristics of the purified 3-hexulosephosphate synthase from the facultative methylotroph Pseudomonas oleovorans were investigated. It could be demonstrated that the dependence of the reaction rate on the rib(ul)ose-5-phosphate as well as the formaldehyde conccntration has a complex shape with the appearence of plateau and trough regions. The shape of the curve is changed in dependence on the fixed level of the second substrate.Nultipk forms of t h e 3-hexulosephosphate synthase were found to be responsible for the generation of the complex kinetic characteristics. By means of ion exchange chromatography i t was possible to separate four active enzyme forms with different kinetic Characteristics. These forms were also found to be interconvertible. This behaviour of the 3-hexulosephosphate synthase is assumed to have the main regulatory function of the enzyme.According to the investigations by KEMP (1972, 1974) and S T R 0 M et al. (1974) the assiniilation of reduced C,-compounds via the ribulose monophosphate cycle is mediated by the enzyme ~-arabino-3-hexulose-6-phosphate synthase (3-hexulosephosphate synthase, HPS). Because of its key position and the importance of theHPS for the methylotrophic metabolism a regulation process is expected t o take place. But in no case anindicationof aneffectiveregulation could be obtained (FERENCI et al. 1974, SAHM et al. 1974, BYKOVSKAYA and VORONXOV 1977. In contrast to this, BABEL and MULLER (1977, 1978) got results which suggest a regulation of the HPS of methanol-utilizing bacteria. The expressions of this regulatory behaviour are coniplex kinetic characteristics with the appearence of intermediary plateau regions. Such a feature could be demonstrated in all obligate and facultative methanol-utilizing bacteria, investigated by BABEL and MULLER, and for this reason it is assumed to be a general substratedependent feature of the HPS in bacteria of this type (BABEL and MULLER 1977,1978, MULLER and BABEL 1977.After the purification of the HPS from the facultative methylotrophic bacteriuni MB 58 (MULLER and BABEL 1978) it was possible to demonstrate that multiple and interconvertible enzyme forms are responsible for the generation of the plateau regions (MULLER 1978, MULLER andBABEL, 1979). The presence of HPS has been shown also in the facultative methylotroph Pseudomonas oleovorans after growth on methanol and methylaniine (LOGINOVA and TROTSENKO 1977). SOKOLOV and TROTSENKO (1978) have purified the enzyme from this source and determined general properties but did not perform kinetic investigations. Kinetic investigations which demonstrated the appearence of intermediary plateau regions by measuring the HPS in crude extract and pernieabilized cells were done by BABEL and MULLER (1978).The purpose of this paper is the investigation of the kinetic behaviour of the purified HPS from Pseudomonas oleovoraizs and the determination of the reasons for the generation of plateau regions with the enzyme from this source. Leipzig)-~ ~

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“…Mechanisms which may be responsible for the generation of such "bumpy" curves are discussed elsewhere MULLER 1977, MULLER and. …”

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 93%

Kinetic properties of the purified 3‐hexulosephosphate synthase from Pseudomonas oleovorans

Müller

Соколов

1979

J of Basic Microbiology

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“…oleovorans) methanol-utilizing bacteria exhibit intermediary plat,eau regions MULLER 1977, 1978). I n contrast to this the enzyme from the methane-utilizing "Methylomonas" GB 3 (BABEL and MULLER 1977) and "MethyZomonas" GB 8 (MULLER 1979) show MICHAELIS-MENTEN dependence.We have attributed a regulatory significance to the appearence of these intermediary plateau regions in analogy to other enzymes with such behaviour (TEIPEL and KOSHLAND 1969, KURGANOV 1975, KURGANOV et al 1976). These plateaus were assumed to be a general feature of the HPS from methanol-(and methylamine-) utilizing bacteria.…”

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confidence: 75%

“…The position of the individual measuring points is highly valid. The standard deviation of the activity after determining it with the aid of the coupled optical test according t o BABEL and MULLER (1977) did not exceed 5 per cent. These investigations were done with the HPS of permeabilized cells of Pseudomonas W6 (procedure according to BABEL and MULLER 1977) a t variable rib(ul)ose-5-phosphate (A) and formaldehyde (B) concentrations, respectively.…”

Section: Analysis Of the Kinetic Datamentioning

confidence: 98%

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A critical analysis of kinetic data of 3‐hexulosephosphate synthases MICHAELIS‐MENTEN or complex characteristics

Müller¹,

Babel²

1980

J of Basic Microbiology

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Investigations of the 3-hexulosephosphate synthase (HPS) from different methylotrophic bacteria have revealed apparent discrepancies in kinetic behaviour. I n all methanol-utilizing species investigated by us the kinetic characteristics showed intermediary plateau regions. Therefore, this behaviour is assumed to be a general feature of the HPS from all non-methane-utilizing methylotrophic bacteria. However, this assumption is in contrast to the results of other authors. To check the validity of our assumption we have analyzed the kinetic data given by others. Indications of the existence of intermediary plateau regions could be found with the enzyme from Arthrobacter globiformis (BYKOVSKAYA and VORONKOV 1977) and Methylomonas aminoiaciens 77a (KATO et al. 1978). Furthermore, biphasic ARRHENIUS plots indicate a multiple character of the HPS from these species as could already be demonstrated with the enzyme from Bacterium MB 58 and Pseudomonas oleovorana. I n addition, causes which may obscure the detection of intermediary plateau regions are demonstrated.Our comparative investigations have shown that the kinetic characteristics of the 3-hexulosephosphate synthase (HPS) from obligate (Pseudomonas W 6 , Methylomonas methylovora) and facultative (Bacterium MB 58, P . oleovorans) methanol-utilizing bacteria exhibit intermediary plat,eau regions MULLER 1977, 1978). I n contrast to this the enzyme from the methane-utilizing "Methylomonas" GB 3 (BABEL and MULLER 1977) and "MethyZomonas" GB 8 (MULLER 1979) show MICHAELIS-MENTEN dependence.We have attributed a regulatory significance to the appearence of these intermediary plateau regions in analogy to other enzymes with such behaviour (TEIPEL and KOSHLAND 1969, KURGANOV 1975, KURGANOV et al. 1976). These plateaus were assumed to be a general feature of the HPS from methanol-(and methylamine-) utilizing bacteria. The differences to the methane-utilizing species have been attributed to the specificity of the substrates utilized (BABEL and MULLER 1977). Both for Bacterium MB58 (MULLER 1978, MULLER and BABEL, in preparation) and P . oleoworans (MULLER and SOKOLOV 1979) multiple and interconvertible forms of the HPS exhibiting a different response to substrate eaturation have been found to generate the intermediary plateau regions. A conception about the regulation of HPS in methylotrophic metabolism is given elsewhere (MULLER 1979, M~L L E R and BABEL, in preparation).However, there are apparent discrepancies between our results and the conclusions derived therefrom and the results obtained by other investigators. Both for the methanol-utilizing Methylomo~as M 15 (SAHM et al. 1976) and Meth~lomona~ arninofuciens (KATO et ul. 1977(KATO et ul. , 1978 these authors have claimed MICHAELIS-MENTEN kinetics and, thus, in general coincidence with the behaviour of the HPS from the methane-utilizing MethyZococcus capsulatus (FERENCI et al. 1974).

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Methanol‐Assimilation durch ein acidophiles Bacterium der Gattung Acetobacter

Babel¹

1984

Acta Biotechnologica

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Generally, methylotrophic bacteria grow optimally in a pH range between 6 and 7.2. The assimilation of methanol can take place via several pathways. Acetobacter methanolicus preiers an acidic pH range for growth, the pH optimum is about 4, and it uses the FBP variant for methanol assimilation.The latter is interesting from a regulatory point of view because phosphofructokinase disappears during growth on glucose, which is assimilated via the hexosemonophosphate pathway. Since Entner‐Doudoroff enzymes and phosphoketolase are absent in A. `ethanolicus as well as in non‐methylotrophic Acetobacter and Gluconobacter species phosphofructokinase becomes a key enzyme of the assimilation of methanol.Although A. methanolicus uses the hexulosephosphate pathway the growth yield on methanol is smaller than with other “hexulosephosphate pathway bacteria” e. g. with obligate methanol assimilating bacteria.At first sight it may appear that the acidic optimum pH is responsible for the smaller growth yield and the discrepancy between the experimental and predicted values.The relationship between the dependence on and the protection from, high external proton concentration on the one hand and the causes of the low growth yield on the other are discussed. Accordingly, A. methanolicus and another heterotrophic acidophiles seem to be acidoresistant above all, their machinery guaranteeing the protection from the high proton concentration is responsible for the acidophily and the low growth efficiency is caused by a simple respiratory chain.

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Kinetik der Hexulose‐6‐phosphat‐Synthase methylotropher Bakterien in vitro und in situ

Cited by 16 publications

References 26 publications

Kinetic properties of the purified 3‐hexulosephosphate synthase from Pseudomonas oleovorans

Kinetic properties of the purified 3‐hexulosephosphate synthase from Pseudomonas oleovorans

A critical analysis of kinetic data of 3‐hexulosephosphate synthases MICHAELIS‐MENTEN or complex characteristics

Methanol‐Assimilation durch ein acidophiles Bacterium der Gattung Acetobacter

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