Рũßłїѕђёď åŗțїćłё #2

 Mattar et al. 2012. ‘Lactose intolerance: diagnosis, genetic and clinical factors.’ Accessed March 28, 2013. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3401057/

Lactose intolerance: diagnosis, genetic and clinical factors:

Lactose is a carbohydrate found in milk. This disaccharide is made up of glucose and galactose subunits. Seventy five percent of the world’s population loses their ability to breakdown the disaccharide into monosaccharide units that are easily digested. Lactase is the enzyme that breaks down lactose products. In infants breakdown is at its max from birth till 2 years. An aging person can fall into a group of lactase non-persistence (hypolactasia) or lactase-persistence activities. Reduction in lactose renders persons lactose intolerant that develop symptoms in identifying the presence of this diagnosis. 

            Individuals with hypolactasia and lactase persistence have identical coding sequences which were confirmed in a study where DNA was collected from subjects in various parts of the world. The LCT-13910CT and LCT-13910TT genotypes were associated with the lactase-persistence phenotype. This indicates that it dominates the person where they is a lactose digester. If the genotype was LCT- 13910CC and LCT-13910T is absent the person suffers from lactose mal digestion.

            The first method for detection of lactose mal digestion was direct biochemical assay of lactase activity from a jejunal sample. This was performed using a glucose oxidase reagent which detects glucose molecules present in the lactose. This method has been replaced by endoscopic duodenal biopsy. The lactose breath test is also a method for determining the presence of lactose in the body. It is based on fermentation of undigested lactose by intestinal flora producing hydrogen, carbon dioxide and methane which is absorbed and eliminated via the lungs. The result of these gases is bloating, abdominal pain, and diarrhea. Undigested lactose acidifies the colon and increases diarrhea while some may experience constipation.

            A false-negative result can occur if antibiotics have been recently consumed within one month of testing or if the pH is too acidic to inhibit bacterial activity or if there has been bacterial growth. The genetic test provides a more direct result where hypolactasia or lactase persistence genotype is found. This was formed due to the discovery of lactase-persistence alleles. This method was deemed better than the breath test since there is no cut off level or dependence on the amount of lactose or influenced by the duration of the test and age of the individual.

            Individuals suffering with this problem need to maintain their intake of calcium due to their restricted milk diet. A deficient in calcium result in bone diseases. A key to management of lactose intolerance is a recommended of no more than 20g of lactose without significant symptoms. A person’s diet changes where they would have to consume it with other foods and prevent lactose tablets. Supplements of calcium and vitamin D are produced which may be expensive to the consumer.  Yoghurt containing live cultures providing endogenous beta galactosidase is an alternative source of calories and calcium and is well tolerated by many lactose-intolerant patients. Lactose hydrolyzed milk is another safe source for patients.

            This article cleared up the effects of an individual suffering from the absence of the enzyme called lactase which breaks down lactose found in dairy products such as milk. It enhances the symptoms of a patient suffering from lactose intolerance and deals with the different mechanisms of detecting lactose in the body and suggests which method is better due to the information gathered.

            Hope you learned something as well…

ȨƞƉ ŏƒ Ąϻȋñö Ąċȉďs & Ƥřȯƫȇȉñs…

Amino Acids-

Proteins are polymers of amino acids joined by peptide bonds. There are 20 different amino acids that make up all proteins on earth. Each of these amino acids has a fundamental design composed of a central carbon (also called the alpha carbon) bonded to:

  • a hydrogen

  • a carboxyl group

  • an amino group

  • a unique side chain or R-group

The characteristic that distinguishes one amino acid from another is its unique side chain and it is the side chain that dictates an amino acids chemical properties. Examples of three amino acids are shown below: 

amino

Glycine is the smallest amino acid. Except for glycine which has a hydrogen as its R-group there is asymmetry about the alpha carbon in all amino acids. All amino acids except glycine can exist in either of two mirror-image forms called stereoisomers which refer to D and L configurations of amino acids. D is more common than the L configuration.

d-lysine

The unique side chains confer unique chemical properties on amino acids, and dictate how each amino acid interacts with the others in a protein. Amino acids can thus be classified as being hydrophobic versus hydrophilic, and uncharged versus positively-charged versus negatively-charged.

 AminoAcids1

Proteins-

Amino acids are covalently bonded together in chains by peptide bonds. If the chain length is short <20 it is called a peptide. Longer chains are called polypeptides or proteins. Peptide bonds are formed between the carboxyl group of one amino acid and the amino group of the next amino acid. Peptide bond formation occurs in a condensation reaction involving loss of a molecule of water. 

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Levels of Protein Structure:

Structural features of proteins are usually described at four levels of complexity:

  • Primary structure: the linear arrangment of amino acids in a protein and the location of covalent linkages such as disulfide bonds between amino acids.
  • Secondary structure: areas of folding or coiling within a protein; examples include alpha helices and pleated sheets, which are stabilized by hydrogen bonding.
  • Tertiary structure: the final three-dimensional structure of a protein, which results from a large number of non-covalent interactions between amino acids.
  • Quaternary structure: non-covalent interactions that bind multiple polypeptides into a single, larger protein. Hemoglobin has quaternary structure due to association of two alpha globin and two beta globin polyproteins. 

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 The different bonds in a protein structure: 

bonds

Proteins are very important molecules in our cells. They are involved in virtually all cell functions. Each protein within the body has a specific function. Some proteins are involved in structural support, while others are involved in bodily movement, or in defense against germs. Proteins vary in structure as well as function. They are constructed from a set of 20 amino acids and have distinct three-dimensional shapes. Below is a tab;e of several types of proteins and their functions.

The table below are some examples of protein functions:

functions

Why You Need Amino Acids Daily?

Foods with amino acids are the building blocks of protein. That means they are responsible for strength, repair and rebuilding inside your body. Your tissues, your cells, your enzymes and your brain all get their nourishment and protection from amino acids. Amino acids make up 75% of the human body and are vital to every part of human function.

You Can’t Store Amino Acids…The problem with amino acids is that they deteriorate. The body will store extra starch and protein as fat, to use later. Amino acids are not stored, but they can be replaced. There are upwards of twenty different kinds of amino acids that form proteins. Some of these the body makes. The ones it cannot make, called the essential amino acids, it must get from constant consumption of food.

The Best Foods: Meat, eggs, and dairy are sources but it is difficult for strict vegetarians and vegans to get all their essential amino acids. Most vegetarian protein foods, such as beans and seeds, contain only portions of the essentials. An exception to this is soy which contains complete proteins.

 

REFERENCES:

http://ghr.nlm.nih.gov/handbook/howgeneswork/protein

http://alevelnotes.com/Protein-Structure/61

http://www.muscleandstrength.com/articles/the-importance-of-amino-acids.html

http://www.fitday.com/fitness-articles/nutrition/vitamins-minerals/foods-rich-in-amino-acids-for-every-meal.html#b

http://www.vivo.colostate.edu/hbooks/genetics/biotech/basics/prostruct.html

http://biology.about.com/od/molecularbiology/a/aa101904a.htm

garden_vegetables_wit_a_ha      Vegetarians have a difficult time:

This post is based on the topic of amino acids and proteins. I can surely tell you from experience it is difficult for a vegetarian to obtain all their essential amino acids by not supplying meat to their daily diet. As a result there must be a presence of a lot of beans to supply the needed nutrients into the body.

What is an essential amino acid?

An essential amino acid is a building block of protein molecules that our bodies cannot produce and need to get from a food source. They are essential because we can not synthesize them from other amino acids or smaller building blocks. Ultimately they are needed to make proteins which build tissues in our bodies.  They are to be obtained from our daily diet.

There are 10 essential amino acids:

  1. arginine
  2. histidine
  3. isoleucine
  4. leucine
  5. lysine
  6. methionine
  7. phenylalanine
  8. threonine
  9. tryptophan
  10. valine

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The failure to obtain enough of even 1 of the 10 essential amino acids has serious health implications and can result in degradation of the body’s proteins. Muscle and other protein structures may be dismantled to obtain the one amino acid that is needed. Unlike lipid and starch the human body does not store excess amino acids for later use.

References:

http://hyperphysics.phy-astr.gsu.edu/hbase/organic/essam.html

http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html