Transferases;
Transferring nitrogenous groups;
Transaminases
BRITE hierarchy

(8S)-8-amino-7-oxononanoate:[protein]-L-lysine aminotransferase (N-carboxylating)

(8S)-8-amino-7-oxononanoate + [protein]-L-lysine + CO2 = (7R,8S)-8-amino-7-(carboxyamino)nonanoate + [protein]-(S)-2-amino-6-oxohexanoate (overall reaction) [RN:R12948];
(1a) (8S)-8-amino-7-oxononanoate + [protein]-L-lysine + NAD(P)H + H+ = [protein]-N6-[(2S,3R)-2-amino-8-carboxyoctan-3-yl]-L-lysine + H2O + NAD(P)+ [RN:R12949 R12952];
(1b) [protein]-N6-[(2S,3R)-2-amino-8-carboxyoctan-3-yl]-L-lysine + CO2 + H2O + NAD(P)+ = (7R,8S)-8-amino-7-(carboxyamino)nonanoate + [protein]-(S)-2-amino-6-oxohexanoate + NAD(P)H + H+ [RN:R12950 R12953]

R12948 R12949 R12950 R12952 R12953;
(other) R12935
Reaction

(8S)-8-amino-7-oxononanoate [CPD:C22463];
[protein]-L-lysine [CPD:C02188];
CO2 [CPD:C00011];
NADH [CPD:C00004];
NADPH [CPD:C00005];
H+ [CPD:C00080];
[protein]-N6-[(2S,3R)-2-amino-8-carboxyoctan-3-yl]-L-lysine [CPD:C22465];
H2O [CPD:C00001];
NAD+ [CPD:C00003];
NADP+ [CPD:C00006]

The enzyme, which participates in biotin biosynthesis, is found in haloarchaea and some cyanobacteria. It forms a conjugant between (7R,8S)-8-amino-7-oxononanoate and an internal lysine residue and catalyses multiple reactions, including a reduction, a carboxylation of the epsilon-amino group of the lysine residue, and an oxidative cleavage of the conjugate to release (7R,8S)-8-amino-7-(carboxyamino)nonanoate. During this process the lysine residue serves as an amino donor and is converted to (S)-2-amino-6-oxohexanoate, resulting in inactivation of the enzyme following a single turnover. cf. EC 2.6.1.105, lysine---8-amino-7-oxononanoate transaminase.

EC 2.6.1.121 created 2021

1  [PMID:32042199]