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Strong Support
mechanistic
Analysis v2
History

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...

33
Pro
0
Against

Mechanism

Synthesis from 1 study

How it works

Mg-GTP makes the enzyme twist into a shape that hides the spots where digestive enzymes would cut it, but Mg-ATP doesn't cause that twist, so the enzyme stays easy to break apart.

Most probable mechanism

In Simple Terms

When Mg-GTP attaches to the enzyme tissue transglutaminase, it causes the enzyme to change its shape in a way that makes it harder for digestive enzymes to cut it apart. Mg-ATP attaches to a different spot and doesn't cause this protective shape change, so the enzyme stays vulnerable.

Causal chain
1

Mg-GTP binds to a specific nucleotide-binding site on tissue transglutaminase

Verified by multiple studies
which leads to
2

Binding of Mg-GTP induces a stable conformational change in the enzyme's three-dimensional structure

Verified by multiple studies
which leads to
3

The conformational change reduces exposure of proteolytic cleavage sites, making the enzyme resistant to degradation by trypsin

Verified by multiple studies
which leads to
4

Mg-ATP binds to a distinct site on the enzyme but fails to induce the same protective structural change

Verified by multiple studies

Evidence from Studies

Supporting (1)

33

Community contributions welcome

33

Regulation of Human Tissue Transglutaminase Function by Magnesium-Nucleotide Complexes

Case-Control Study
In Vitro
1998 Jan 16

Contradicting (0)

0

Community contributions welcome

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.

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Source Study

Regulation of Human Tissue Transglutaminase Function by Magnesium-Nucleotide Complexes

Score: 33
DOI: 10.1074/jbc.273.3.1776

Similar Assertions

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.

33
0
85%

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.

33
0
85%

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.

33
0
78%

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 differences in how the enzyme interacts with each molecule.

33
0
78%

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.

28
0
75%