EC Number   |
Reaction |
Reference |
|---|
    2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
Escherichia coli SPDS follows the ping-pong mechanism, in which an aminopropylated enzyme intermediate was formed by the interaction of SPDS with dcSAM, prior to reaction with putrescine |
723164 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
first discovered |
639704 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
general mechanistic hypothesis for the aminopropyl transfer reaction |
672272 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
Michaelis-Menten kinetics |
489868 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
ping-pong mechanism with a propylaminated form of the enzyme as an obligatory intermediate |
639702 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
random order or ordered mechanism in which both substrates bind before the release of the products |
639697 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
reaction mechanism involving a gate-keeping loop, active site and substrate binding structures and involved residues, structure-function relationship analysis by molecular dynamics simulations of a homology model |
672560 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
single displacement reaction |
639702 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
the enzyme possesses a Rossmann-like fold with a distinct active site, the enzyme from Helicobacter pylori lacks the gatekeeping loop that facilitates substrate binding in other PAPTs, active site structure |
677059 |
| 2.5.1.16 | S-adenosyl 3-(methylsulfanyl)propylamine + putrescine = S-methyl-5'-thioadenosine + spermidine |
this mechanism depends on a conserved Asp (residue 173 in hSpdS) in the active site that interacts with the bound amine substrate to deprotonate the attacking nitrogen atom of the amine. This interaction is reinforced by additional interactions of this nitrogen atom with the hydroxyl group of a conserved Tyr (residue 79 in hSpdS) and a backbone carbonyl group (Ser174 in hSpdS). These interactions allow the attack on the methylene carbon atom of the aminopropyl group attached to the sulfonium center of dcAdoMet. Electron transfer to this sulfur atom completes the reaction forming S-methyl-5'-thioadenosine and the polyamine product. The positively charged sulfonium ion is a critical part of the reaction |
723723 |
