Apolipoprotein and their function, chromium as

muscle building tissue and relationship of chromium

and lipid profile

Preeti Bartwal

Apolipoprotein

• Apolipoproteins are proteins that bind lipids to form lipoproteins.• They transport the lipids through the lymphatic  and circulatory 

     systems.• The  lipid  components  of  lipoproteins  are  insoluble  in  water. 

However,  because  of  their  detergent-like  (amphipathic) properties,  apolipoproteins  and  other  amphipathic  molecules (such  as phospholipids)  can  surround  the  lipids,  creating  the lipoprotein  particle  that  is  itself  water-soluble,  and  can  thus  be carried through water-based circulation (i.e. blood, lymph).

• Apolipoproteins also  serve as enzyme cofactors,  receptor ligands, and  lipid  transfer  carriers  that  regulate  the  metabolism  of lipoproteins and their uptake in tissues.

Types of apolipoproTein

There are two major types of apolipoproteins.

1.Apolipoproteins B form low-density lipoprotein ("bad cholesterol") particles. These proteins have mostly beta-sheet structure and associate with lipid droplets irreversibly.

2. Other apolipoproteins form high-density lipoprotein ("good cholesterol") particles. These proteins consist of alpha-helices and associate with lipid droplets reversibly. During binding to the lipid particles these proteins change their three-dimensional structure.

Classes of apolipoproTeins

There are six classes of apolipoproteins and several sub-classes:•A (apo A-I, apo A-II, apo A-IV, and apo A-V)•B (apo B48 and apo B100)•C (apo C-I, apo C-II, apo C-III, and apo C-IV)•D•E•H

Functions

• In lipid transport, apolipoproteins function as structural 

     components of lipoprotein particles, cofactors for 

     enzymes and ligands for cell-surface receptors. • In particular, apoA1  is  the major protein component of high-

density lipoproteins; • apoA4 is thought to act primarily in intestinal lipid absorption.• Further,  apoE  is  a blood plasma  protein that  mediates  the 

transport  and  uptake  of cholesterol and  lipid  by  way  of  its high  affinity  interaction  with  different cellular receptors, including the low-density lipoprotein (LDL) receptor. 

• They  are  enzyme  coenzymes  (C-II  for  lipoprotein  lipase  and A-I for lecithin-cholesterol acyltransferase)

• Lipid transport proteins• Ligands  for  interaction  with  lipoprotein  receptors  in  tissues 

(apoB100 and apoE for LDL-receptors, apoA-I for HDL receptors)• Plasma  lipoprotein  metabolism  is  regulated  and  controlled  by 

the  specific  apolipoprotein  (apo-)  constituents  of  the  various lipoprotein  classes.  The  major  apolipoproteins  include  apoE, apoB, apoA-I, apoA-II, apoA-IV, apoC-I, apoC-II, and apoC-III. 

• Specific apolipoproteins function in the regulation of lipoprotein metabolism  through  their  involvement  in  the  transport  and redistribution of  lipids among various cells and tissues,  through their  role  as  cofactors  for  enzymes  of  lipid  metabolism,  or through  their  maintenance  of  the  structure  of  the  lipoprotein particles.

Chromium as a musCle building tissue

• The problem is often worsened by the fact that both exercise and high sugar consumption increase the body's need for chromium. Chromium deficiency can cause serious problems related to weight management, energy and stamina, muscle-building, and much more.

• Chromium Increases Muscle Size and Strength Numerous studies have now proven that chromium picolinate can substantially increase muscle growth, which is believed to happen because together insulin and chromium ensure that protein gets out of the blood efficiently and into the cells where it can be assembled into new muscle tissue (and new heart, liver and kidney tissue, as well.) According to Dr. Jeffrey Fisher, author of The Chromium Program, chromium can dramatically help build muscle and reduce fat, while significantly contributing to lower cholesterol and improved blood sugar metabolism.

relationship of Chromium and lipid profile

• Low chromium levels can increase blood sugar, triglycerides (a type of fat in the blood), cholesterol levels, and increase the risk for a number of conditions, such as diabetes and heart disease.

• Chromium plays an important role in the efficient uptake of blood sugar and conversion to glycogen, which contributes to improved energy, stamina and endurance.

• Proper chromium nutrition leads to a decreased requirement for insulin and also an improved blood lipid profile.