Cloned (Comment) | Organism |
---|---|
gene LAG2, recombinant expression of codon-optimized LAG2 as N-terminally FLAG-tagged enzyme in Saccharomyces cerevisiae membranes | Arabidopsis thaliana |
Protein Variants | Comment | Organism |
---|---|---|
additional information | complementation of the growth defect of DELTAlag1/DELTAlac1 yeast deletion mutant by recombinant GST-/FLAG-tagged LOH2. Complementation with LOH2 leads to the accumulation of C16-containing inositolphosphoceramides and ceramides indicating this isoform's preference for C16 fatty acids. Microsomes isolated from LOH2 overexpressing plants showed high levels of C16-ceramide synthase activity compared to microsomes from wild-type plants, indicating that LOH2 overexpression results in accumulation of functional enzyme | Arabidopsis thaliana |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
fumonisin B1 | mixed mode of inhibition with respect to the long-chain base | Arabidopsis thaliana |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Michaelis-Menten kinetics | Arabidopsis thaliana | |
0.023 | - |
sphinganine | pH 7.5, 30°C, LOH2 | Arabidopsis thaliana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
microsome | - |
Arabidopsis thaliana | - |
- |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Ca2+ | activates | Arabidopsis thaliana | |
Mg2+ | activates at 2 mM | Arabidopsis thaliana | |
Mn2+ | activates | Arabidopsis thaliana | |
additional information | poor effect observed by 0.001 mM of Cu2+, Zn2+, or Co2+ | Arabidopsis thaliana |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
palmitoyl-CoA + sphinganine | Arabidopsis thaliana | - |
CoA + N-palmitoylsphinganine | - |
? | |
palmitoyl-CoA + sphingosine | Arabidopsis thaliana | - |
CoA + N-palmitoylsphingosine | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | Q9LJK3 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | specificity of three different isoforms of ceramide synthase, denoted LOH1, 2 and 3, for a range of long-chain base (LCB) and acyl-CoA substrates. The contribution of each of these isoforms to the synthesis of ceramide is investigated by in vitro ceramide synthase assays, overview. The plant LCB phytosphingosine is efficiently used by the LOH1 and 3 isoforms, with LOH1 having the lowest Km for the LCB substrate of the three isoforms. In contrast, sphinganine is used efficiently only by the LOH2 isoform. Acyl-CoA specificity is also distinguished between the three isoforms with LOH2 being almost completely specific for palmitoyl-CoA, while the LOH1 isoform shows greatest activity with lignoceroyl- and hexacosanoyl-CoA. Unsaturated acyl-CoAs are not used efficiently by any isoform while unsaturated LCB substrates are preferred by LOH2 and 3. LOH2 shows poor activity with phytosphingosine. LOH2 is unable to use any acyl-CoA substrates greater than C18 and shows very strong preference for C16 acyl-CoA. Recombinant LOH2 shows maximum activity with the d18:1(4E) LCB about 6 times that with the d18:0 LCB, eventhough d18:1(4E) is not observed in Arabidopsis leaves. Rather d18:2(4E/8Z) or d18:2(4E/8E) are found in selected tissues such as pollen. LOH2 shows enhanced activity towards DELTA4 unsaturated LCB substrates | Arabidopsis thaliana | ? | - |
? | |
palmitoyl-CoA + sphinganine | - |
Arabidopsis thaliana | CoA + N-palmitoylsphinganine | - |
? | |
palmitoyl-CoA + sphingosine | - |
Arabidopsis thaliana | CoA + N-palmitoylsphingosine | - |
? |
Synonyms | Comment | Organism |
---|---|---|
ceramide synthase | - |
Arabidopsis thaliana |
LAG1 longevity assurance homolog 2 | - |
Arabidopsis thaliana |
LAG12 | - |
Arabidopsis thaliana |
LOH2 | - |
Arabidopsis thaliana |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
30 | - |
assay at | Arabidopsis thaliana |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.5 | - |
assay at | Arabidopsis thaliana |
Ki Value [mM] | Ki Value maximum [mM] | Inhibitor | Comment | Organism | Structure |
---|---|---|---|---|---|
0.00097 | - |
fumonisin B1 | pH 7.5, 30°C, LOH2 | Arabidopsis thaliana |
General Information | Comment | Organism |
---|---|---|
physiological function | distinct roles and modes of regulation for each of the ceramide synthases in Arabidopsis thaliana sphingolipid metabolism. Ceramides are organizing components of sphingolipids in the eukaryotic cell. Three ceramide synthase isoforms are found in Arabidopsis thaliana each with specific substrate preferences and sensitivity to inhibitors and activators, overview. Isozyme LOH2 is required for the synthesis of ceramides with dihydroxy-long-chain bases and C16 fatty acids | Arabidopsis thaliana |