ScienceNot yet confirmed elsewhere1 publisher2 min readPublished
Glucose and the much larger dextran help the enzyme PFKP stay active at higher temperatures
Ruhr University Bochum researchers found glucose and the much larger dextran both helped PFKP retain activity at higher temperatures. They attribute it to weak, reversible contacts among the surrounding molecules, the enzyme and its substrates.
The Scientist · Science desk
What happened
- The team measured PFKP activity across temperatures, assessed its structural stability and ran molecular simulations, all in controlled solutions with crowders of different sizes and chemical properties.
- Every crowded solution reduced PFKP activity at lower temperatures.
- The simulations showed that the surrounding molecules can influence regions near the active site, affecting enzyme flexibility and how substrates are positioned.
- The work was published in Angewandte Chemie International Edition.
Why it matters
- constraint An assay run at a single temperature sees only part of the pattern: crowding cost activity at lower temperatures, and the sugars' benefit showed up at higher ones.
- decision Labs that choose a crowder to mimic a cell interior can no longer treat the choice as a size match. On this evidence the chemistry of the crowder belongs in the selection.
- constraint The experiments covered the platelet isoform of one enzyme, so any extension to other metabolic enzymes is still a prediction.
Glucose and dextran make a useful pair for the question Simon Ebbinghaus framed in the release. "A key question has therefore remained open: Is it mainly the limited space around an enzyme that matters, or is the chemical nature of its neighbors equally important?" he said [10]. Dextran is a glucose polymer [4], so the two sugars share their chemistry and differ widely in size. Their similar effects are what let the team set size aside as the sole explanation [2].
The proposed explanation is a balance. An enzyme needs enough flexibility to carry out its reaction, and it also has to keep its substrates placed correctly [11]. The release says sugar-based environments appear to tune that balance and make PFKP more robust at elevated temperatures [12]. It adds that the enzyme is not simply protected from unfolding, and that its dynamics and catalytic behavior are shaped by its local environment [13].
Rastogi said that at higher temperatures "the results revealed a striking difference" [14]. The release does not say how large that difference was, over what temperature range, how many crowders were tested or how many replicates stand behind it. Without those figures the effect size cannot be judged from the release.
The thing this doesn't tell you is how PFKP behaves inside a cell, where it is surrounded by proteins, sugars and many other molecules [15]. A solution with chosen crowders is a simpler mixture than that. In our view the narrow finding holds for the crowders tested, in solution: size alone does not set how well PFKP keeps working as temperatures rise. The cellular version is still a hypothesis.
Ebbinghaus's own wording is hedged. "The chemical composition of the surrounding molecules may actively influence how metabolic enzymes respond to stress," he said [16]. According to the release, it is left to later studies to establish whether cells use local chemical surroundings like these to keep metabolism going when conditions are hard [17].
What to watch
- Tests of PFKP in mixtures closer to cell contents, which the authors leave open as the next question.
- The paper's activity-versus-temperature data, crowder count and replicates, which would give the effect size the release omits.
- Whether other glycolytic enzymes show the same sugar-versus-size pattern when crowders are matched for size.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
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- Adoption
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- Hype gap+10
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- [1]
A team led by professor Simon Ebbinghaus and Dr. Harshita Rastogi at Ruhr University Bochum and the Research Center for Chemical Sciences and Sustainability investigated the platelet isoform of phosphofructokinase-1 (PFKP), a central enzyme in glucose metabolism.
- [2]
Because glucose and the much larger dextran had similar effects, molecular size alone could not explain the result.
- [3]
Sugar-based molecules, including glucose and dextran, helped PFKP retain activity over a broader temperature range at higher temperatures.
- [4]
Dextran is a glucose polymer.
- [5]
The researchers studied PFKP in controlled solutions containing crowding molecules of different sizes and chemical properties, measured how enzyme activity changed with temperature, assessed its structural stability and used molecular simulations to examine interactions that cannot be observed directly in experiments.
- [6]
All crowded environments reduced PFKP activity at lower temperatures.
- [7]
The simulations showed that the surrounding molecules can influence regions near the enzyme's active site, affecting both enzyme flexibility and substrate positioning.
- [8]
The work was published in the journal Angewandte Chemie International Edition.
- [9]
The findings point to the importance of 'soft' chemical interactions: weak, reversible contacts among the surrounding molecules, the enzyme and its substrates.
- [10]
"A key question has therefore remained open: Is it mainly the limited space around an enzyme that matters, or is the chemical nature of its neighbors equally important?"
- [11]
An enzyme must be flexible enough to catalyze its reaction while holding its substrates in the correct position.
- [12]
Sugar-based environments appear to tune this balance, making PFKP more robust at elevated temperatures.
- [13]
The enzyme is not simply protected from unfolding; its dynamics and catalytic behavior are shaped by its local environment.
- [14]
Rastogi said that at higher temperatures "the results revealed a striking difference".
- [15]
Inside cells, enzymes are surrounded by proteins, sugars and many other molecules.
- [16]
"The chemical composition of the surrounding molecules may actively influence how metabolic enzymes respond to stress,"
- [17]
Future research will need to determine whether cells exploit such local chemical environments to preserve metabolic activity under challenging conditions.
Sources
1 independent publisher whose own reporting we read for this story.
- phys.orgChemical surroundings, not size alone, help glucose-processing enzyme stay active as temperatures rise
1 article · October 13, 2026
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