Protein expression vectors Please help - (Jun/02/2011 )

Hi,

I would be grateful for any help. I want to express a called human lysyl oxidase. Lysyl oxidase is synthesized and exported to the extracellular
space as a 50 kDa inactive preproprotein. Once in the extracellular space, it is cleaved at a specific Gly–Asp bond (Gly168–Asp169 for
human LOX) by procollagen C-proteinase to yield the active 29 kDa enzyme <7–9>.
at NCBI it says lysyl oxidase is a 415 AA protein. i was looking at 2 vectors

https://www.qiagen.com/geneglobe/qiageneview.aspx?ID=EEC0028140
protein def protein-lysine 6-oxidase isoform 1 preproprotein 417 AA

https://www.qiagen.com/geneglobe/qiageneview.aspx?ID=EEC0435596
protein def lysine 6-oxidase isoform 2

when i took weight of the AA sequence for the 1st it was like 49 kDa
the second was like 18 Kda

it papers where they express and purify this protein they get a SDS-PAge band around 30 KDa.
How can this be and which vector do i get to express this protein?

PLEASE HElP!!!!

silvepa23 on Thu Jun 2 23:20:56 2011 said:

sds-page will give you an estimate of molecular weight. the apparent weight can be influenced by a number of factors including amino acid composition and sds binding.

I'm not sure which paper you refer to. This protein appears to be a secreted protein. If it's expressed in E.coli, it will mostly close to the calculated MW. If expressed in mammalian cells, it may looks bigger on SDS-PAGE due to modifications like glycosylation.