Literature summary for 2.5.1.22 extracted from

Wu, H.; Min, J.; Zeng, H.; McCloskey, D.E.; Ikeguchi, Y.; Loppnau, P.; Michael, A.J.; Pegg, A.E.; Plotnikov, A.N.
Crystal structure of human spermine synthase: implications of substrate binding and catalytic mechanism (2008), J. Biol. Chem., 283, 16135-16146.

Crystallization (Commentary)

Crystallization (Comment)	Organism
in complex with 5'-methylthioadenosine and spermidine and with 5'-methylthioadenosine and spermine. Enzyme is a dimer of two identical subunits. Each monomer has three domains, a C-terminal domain, which contains the active site and is similar in structure to spermidine synthase, a central domain made up of four beta-strands, and an N-terminal domain with remarkable structural similarity to S-adenosylmethionine decarboxylase	Homo sapiens

Crystallization (Comment)

Organism

in complex with 5'-methylthioadenosine and spermidine and with 5'-methylthioadenosine and spermine. Enzyme is a dimer of two identical subunits. Each monomer has three domains, a C-terminal domain, which contains the active site and is similar in structure to spermidine synthase, a central domain made up of four beta-strands, and an N-terminal domain with remarkable structural similarity to S-adenosylmethionine decarboxylase

Homo sapiens

Protein Variants

Protein Variants	Comment	Organism
D201A	40000fold decrease in ratio kcat/Km value	Homo sapiens
D201N	40000fold decrease in ratio kcat/Km value	Homo sapiens
D276N	250000fold decrease in ratio kcat/Km value	Homo sapiens
E353Q	1000fold decrease in ratio kcat/Km value	Homo sapiens
additional information	deletion of the N-terminal domain leads to a complete loss of spermine synthase activity	Homo sapiens

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
additional information	-	additional information	ratio of kcat/Km value of wild-type is 40000 for substrate spermidine, and 71000000 for S-adenosyl-L-methioninamine, respectively	Homo sapiens

Organism

Organism	UniProt	Comment	Textmining
Homo sapiens	P52788	-	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
S-adenosyl-L-methioninamine + spermidine	-	Homo sapiens	5'-methylthioadenosine + spermine	-	?

Turnover Number [1/s]

Turnover Number Minimum [1/s]	Turnover Number Maximum [1/s]	Substrate	Comment	Organism
0.0015	-	spermidine	mutant D201A, pH 7.5, 37°C	Homo sapiens
0.0015	-	spermidine	mutant D201N, pH 7.5, 37°C	Homo sapiens
0.0022	-	spermidine	mutant D276N, pH 7.5, 37°C	Homo sapiens
0.64	-	spermidine	mutant E353Q, pH 7.5, 37°C	Homo sapiens
32	-	spermidine	wild-type, pH 7.5, 37°C	Homo sapiens