Amended on 22 January 2018

Brain enzymes are mainly membrane glycoproteins. In order to understand the diseases of brain, we have purified pig brain lipoamidase (please see file; Purify Brain Lipoamidase). It is interesting that brain membrane enzyme has multiple substrates (please see file; Multiple Hydrolase LIP).

By the way, I have found that a GSD-1b patient (3y4mo, female; biotin deficiency with status epilepticus) has Huntingtin-interacting protein HIP3RP/ZDHHC13 at 3.1 μg/mg of serum protein in her serum (please see file; Alopecia Dr. K. Abe). Since ZDHHC13 is a multi-pass membrane protein, and direct assay of Mg2+ active transport (activity of membrane protein) may become important in this disease of status epilepticus.

I have started my research about bacterial membrane proteins. E. coli RodA protein is membrane protein and determines cell morphology (please see file; P1kc RodA E,coli). Mercury resistance is also associated to membrane proteins (please see file; Resistance to Hg).

Hi Wei Li,

The cell membrane isolates the interior of a cell from its surrounding. This allows it to maintain its identity and function. However, considering that an average human is made up of about a trillion cells arranged into an intricate networks of tissue and organs, it is critical that these cells perform their various functions in concert. So, each must also be able to sense its surroundings and act appropriately.

These functions are performed by membrane proteins embedded in the cell surface membrane. They serve as a bridge between the environment outside as well as inside. These proteins are of particular interest as they have two important functions: (i) that of sensing a change in the environment; and subsequently (ii) triggering a change in the cell interior or behaviour in response. In this way, membrane proteins allow cells to coordinate their function, letting tissues and organs perform much more complex tasks. This is why almost 50% of the human genome encodes membrane proteins.

Any failure of these proteins in their function often leads to pathologies that result in severe illness, such as nephrogenic diabetes insipidus, hypergonadotropic ovarian failure, etc. Understanding the molecular mechanisms leading to development of these diseases is critical to the development of effective treatments. This requires the study of the membrane proteins involved under carefully controlled conditions. For this reason, many researchers try to produce these proteins in cells of their choice or even using cell-free conditions.

I hope this helps!

Dear Tan

50% could be estimated, 20~30% could be relatively accurate.

References:

Article Genome-wide analysis of integral membrane proteins from euba...

Hi Wei Li,

You're quite right. I was sloppy with my number. Thanks for the correction.

Best regards,

Darren

Further amended on 30 January 2018

My experience has suggested that normal- and LC (liver cirrhosis)- livers have c.a. 50% membrane proteins (normal liver tissue of pseudo-liver cancer has 51.8% of membrane proteins as assessed by ultracentrifugation and PDMD method), but cancer cells and Escherichia coli cells have 20-30% membrane proteins (please see file; HepG2 Fucoidan, and my unpublished observation at The University of Tokyo, Tokyo, Japan for E. coli).

LC tissue of named No.6 person has 42.0% of membrane proteins, and HCC (hepatocellular carcinoma) tissue of the same person has 29.3%. LC tissue with leprosy has 49.8% membrane. HCC tissue with PBC (primary biliary cirrhosis) has only 14.8% membrane. Normal fetal hepatocyte Hc cells has interestingly 27.2% of membrane, which is similar to HCC tissue. Therefore, immortal normal cell and cancer cell have low content of membrane compartment (please see page 110 of the file; HepG2 Fucoidan). I am very grateful to the five persons (three persons sadly deceased and two persons happily survived), who have kindly provided us the important liver biopsies.

Fucoidan increases membrane compartment to normal level in HepG2 as reportedly in the file “HepG2 Fucoidan”. I would like to say thank you very much to Hon.Prof.Dr. Iwao Kusaka (The Institute of Applied Microbiology, University of Tokyo, Tokyo, Japan) to indicating me about the importance of metabolism of the membrane compartment (please see file; Dr. Kusaka Membrane).

Dear Hayakawa

You are right. normal liver cells and possible other cells are especial cases. 20~30% of membrane protein genes in genome is an average value for all prokaryotic and eukaryotic cells.

Your results are very useful to basic drug development of hepatocarcinoma.

Further added on 2 February 2018

Prion protein is a metal-binding GPI-anchored membrane glycoprotein (Mr 33,000, Hydrophobicity (Hyd) 0.547), and the glycosylation pattern (the amount of mono-, di- and non-glycosylated forms or glycoforms) seems to differ in normal and CJD prion.

Amyloid-beta A4 protein/Alzheimer disease amyloid protein is also a metal-binding single-pass type I membrane glyco-phospho-protein (Mr 130,000, Hyd 0.488), which seems to be similar to brain lipoamidase (please see file; Purify Brain Lipoamidase).

Since fucoidan normalizes the membrane compartment (please see file; HepG2 Fucoidan) possibly via the glyco-chains, many brain diseases such as Prion disease (CJD), Alzheimer disease, and Dementia seem to be also cured by the fucoidan.