Hi Joseph, LDLR sequences and related receptors (LRP-1,-2) are highly conserved across species.

If you are looking for a polyclonal, ask them if it was made using the whole LDLR as the immunogen. If so, the antibody will almost certainly react with hamster LDLR.

I have searched for LDLR in my human protein database (please see file; HepG2 Fucoidan).

I have found only three cases.

Healed hepatocte HepG2 (cultured with fucoidan at 0.102 mg/mL for 3 days) has Low-density lipoprotein receptor/LDL receptor/LDLR at 4.0 μg/mg cell protein. This healed cell has Hemagglutinin (Influenza A virus/FluA) at 1.35, and Nucleoprotein (Influenza C virus/FluC) at 0.95 μg/mg cell protein, respectively. It is noteworthy that Flu virus is relatively resistant against Fucoidan for 3 days, and therapy for 3 weeks may be required to effectively reduce the Flu virus in the HepG2.

Serum of GSD-1b (biotin deficiency) has Low density lipoprotein (LDL) receptor-related protein-associated protein 1/RAP/A2MR-associated protein at 10.7 μg/mg serum protein.

Serum of 1y4mo girl (healthy) has Low-density lipoprotein receptor-related protein 1B/LRP-1B at 7.7 μg/mg serum protein, and also has Neuraminidase (Influenza A virus/FluA) at 9.0 μg/mg serum protein.

Therefore, my important point is as follows; i.e., LDLR gene seems to be under the control or up-regulated by the Flu virus.

Therefore, my second point is that species differences and infection by virus is most important issue in gene expression study.

By the way, Famous Late Prof. Dr. Kunio Yamauchi (Department of Agricultural Chemistry, The University of Tokyo, Yayoi-cho, Bunkyo-ku, Tokyo, Japan) has found that α- S2 Casein and β- Lactoglobulin genes are absent in humans.

Italian Pediatricians Bertino E et al. have shown it in "Acta Biomed Ateneo Parmense. 1997;68 Suppl 1:15-9. Absence in human milk of bovine beta-lactoglobulin ingested by the mother. Unreliability of ELISA measurements. Bertino E, Coscia A, Costa S, Farinasso D, Prandi G, Fabris C, Cavaletto M, Giuffrida MG, Conti A., Cattedra di Neonatologia, Università di Torino, Italy". This paper also indicated the unreliable or non-quantitative nature of ELISA method.

I have quantitatively proven the presence of α- S2 Casein at 50.3 μg/mg of milk protein and β- Lactoglobulin at 27.5 μg/mg of milk protein only in the bovine milk by PDMD method (my unpublished observation).

Further, I have recently found that milk biotinidase is present in human breast milk at 5.5 μg/mg of milk protein, but absent in bovine milk (please see file; The Fascio effect).

Furthermore, major component proteins of human breast milk and bovine milk are shown as a reference (our unpublished result). Species differences between humans and bovine seem to be very big.

Bovine milk of Japanese cattle

1st V-type proton ATPase 116 kDa subunit a isoform 1/Vacuolar proton pump subunit 1/Vacuolar adenosine triphosphatase subunit Ac116 at 126.4 μg/mg of milk protein

2nd Solute carrier family 43 member 3/SLC43A3 at 124.9

3rd α-Lactalbumin/Lactose synthase B protein at 110.0

4th Negative regulator of reactive oxygen species/Leucine-rich repeat-containing protein 33 at 104.3

5th α s1 Casein at 101.1

6th Aldehyde oxidase/Azaheterocycle hydroxylase 1 at 81.9

7th β- Casein at 78.8

8th κ- Casein at 74.3

9th Sialidase/Neuraminidase (Salmonella typhimurium) at 58.2

10th α- S2 Casein at 50.3

11th β- Lactoglobulin at 27.5

12th Fibrillin-1/MP340 at 15.3

Human breast milk of healthy Japanese woman

1st α-Lactalbumin/Lactose synthase B protein/Lysozyme-like protein 7 at 156.0

2nd β-Casein at 127.5

3rd Lactoferrin at 83.0

4th RING finger protein 86/Tripartite motif-containing protein 2/UBE2D1-dependent E3 ubiquitin-protein ligase at 55.0

4th Vacuolar protein sorting-associated protein 13B/Cohen syndrome protein 1 at 55.0

6th Major capsid protein/MCP (Saimiriine herpesvirus 2/SaHV-2) at 51.0

7th Protein Smp (Escherichia coli) at 40.3

8th Tetraspanin-14/Transmembrane 4 superfamily member 14 at 33.8 9th Lysozyme at 30.9

10th α s1 Casein at 30.0

11th MARCKS-related protein/Macrophage myristoylated alanine-rich C kinase substrate at 25.8

12th Human breast milk lipoamidase at 23.0 (please see file; mLIP purify)

Good for you Kou and your point is?

@ Kou Hayakawa

That was not the answer I was looking for. I just want to know if anyone has used an antibody for LDLR in Cho cells.

My point is that if you want to get anti-Hamster-LDLR-IgG, please specifically make the IgG immunized by purified chinese hamster LDLR. Slow and steady wins the game,,,,

Human LDLR has 5 of N-Glyco chains and 1 phosphothreonine. O-Glycochains may be present more than 8 chains.

Hamster LDLR has 3 of N-Glyco chains and 2 phosphothreonines. O-Glycochains may be present more than 8 chains.

Mouse LDLR has 3 of N-Glyco chains and 2 phosphothreonines and 1 phosphoserine. O-Glycochains may be present more than 9 chains.

Rabbit LDLR has 3 of N-Glyco chains and 1 phosphothreonines and 1 phosphoserine. O-Glycochains may be present more than 7 chains.

These chemical differences may also indicate the presence of species differences.

So you may sadly recognize or find notorious false positive results in notorious immuno assay by using commercially available IgGs or antibodies.

Hi Joseph Bower ,

I did a search for you on BenchSci and found 3 LDLR antibodies that have been published in CHO cells. (https://landing.benchsci.com/academic)

Please see attached for more info.

I hope this helps!

Maurice

Great thanks.