Human tissue transglutaminase enzyme uses two magnesium-bound nucleotides, Mg-ATP and Mg-GTP, as substrates for hydrolysis, and Mg-ATP binds more tightly to the enzyme than Mg-GTP, suggesting...

Pro

Against

Mechanism

Synthesis from 1 study

How it works

This enzyme can break down two similar energy molecules, but it grabs one much tighter than the other. The tighter one blocks the enzyme from breaking down the looser one, while the looser one changes the enzyme’s shape to turn off a different job it does. So which molecule is around determines how...

Most probable mechanism

In Simple Terms

A specific enzyme in human tissue can break down two similar energy molecules, but it holds onto one much tighter than the other. When the tighter-binding molecule attaches, it blocks the enzyme from breaking down the other molecule, while the looser-binding molecule changes the enzyme’s shape to reduce its other activity. This means the enzyme’s behavior is controlled by which molecule is present and how strongly it sticks.

Causal chain

Mg-ATP binds to a specific site on tissue transglutaminase with higher affinity than Mg-GTP, resulting in more stable enzyme-nucleotide complex formation.

Verified by multiple studies

which leads to

Mg-GTP binds to a distinct site on tissue transglutaminase, inducing a conformational change that reduces the enzyme’s transglutaminase activity.

Verified by multiple studies

which leads to

Binding of Mg-ATP competitively inhibits the hydrolysis of Mg-GTP by occupying its binding site or altering enzyme dynamics, without inducing the same conformational change as Mg-GTP.

Verified by multiple studies

which leads to

The differential binding affinities and opposing functional effects allow Mg-ATP to dominate regulatory control over Mg-GTP hydrolysis, while Mg-GTP suppresses the enzyme’s cross-linking function.

Verified by multiple studies

Evidence from Studies

Supporting (1)

Community contributions welcome

Regulation of Human Tissue Transglutaminase Function by Magnesium-Nucleotide Complexes

Case-Control Study

In Vitro

1998 Jan 16

Contradicting (0)

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No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Regulation of Human Tissue Transglutaminase Function by Magnesium-Nucleotide Complexes

Score: 33

DOI: 10.1074/jbc.273.3.1776

Similar Assertions

The enzyme transglutaminase in human tissues has separate molecular pockets that bind Mg-GTP and Mg-ATP, allowing it to respond differently to each molecule based on their chemical structure.

91%

In human tissue transglutaminase, magnesium-bound ATP strongly blocks GTP breakdown at low concentrations, while magnesium-bound GTP only weakly blocks ATP breakdown even at high concentrations, showing that the two molecules affect each other's activity unequally.

85%

In human tissue transglutaminase, the rates at which the enzyme breaks down GTP and ATP change in a coordinated way when the protein is shortened at its end, indicating that both molecules are processed by the same active site.

83%

Magnesium-bound guanine nucleotides (Mg-GTP, Mg-GDP, Mg-GMP) reduce the activity of human tissue transglutaminase at specific concentrations, while magnesium-bound adenine nucleotides do not, indicating that the enzyme is selectively regulated by guanine-based molecules.

82%

When Mg-GTP binds to the enzyme tissue transglutaminase, it prevents the enzyme from being broken down by trypsin; Mg-ATP does not have this effect, suggesting that Mg-GTP changes the enzyme's shape in a way that makes it more stable.

78%