Glycine

What is Glycine

Chemical Name:2-aminoethanoic acid

Molecular Weight:75.1

Structrual Formula:

Nitrogen Content: 18.66%

Glycine (13, 14)

Glycine is the simplest amino acid and is the only amino acid that is not optically active (it has no stereoisomers). This amino acid is essential for the biosynthesis of nucleic acids as well as of bile acids, porphyrins, creatine phosphate, and other amino acids. On a molar basis, glycine is the second most common amino acid found in proteins and enzymes being incorporated at the rate of 7.5 percent compared to the other amino acids. Glycine is also similar to gamma-aminobutyric acid and glutamic acid in the ability to inhibit neurotransmitter signals in the central nervous system.

Glycine and nervous system (14, 219)

Glycine is an inhibitory neurotransmitter in the central nervous system, especially in the spinal cord. When glycine receptors are activated, chloride ions enter the neuron and the cell undergoes a hyperpolarization. Thus the cell tends to be in an inhibited state. Strychnine, a drug that cause convulsions, acts by blocking these glycine receptors. Glycine is also involved as a co-agonist of glutamate for the activation of NMDA receptors.

Glycine is the major inhibitory neurotransmitter in the brainstem and spinal cord, where it participates in a variety of motor and sensory functions. Glycine is also present in the forebrain, where it has recently been shown to function as a coagonist at the N -methyl-D- aspartate (NMDA) subtype of glutamate receptor. In the latter, context glycine promotes the actions of glutamate, the major excitatory neurotransmitter (for a discussion of glycine’s role as a coagonist of the NMDA receptor. Thus, glycine subserves both inhibitory and excitatory functions within the CNS.

Glycine and Protein Structure (221)

Glycine is very evolutionarily stable at certain positions of some proteins (for example, in cytochrome c, myoglobin, and hemoglobin), because mutations that change it to an amino acid with a larger side chain could break the protein’s structure. Most proteins contain only small quantities of glycine. A notable exception is collagen, which is about one-third glycine Glycine is a protein amino acid found in the protein of all life forms. It is the simplest amino acid in the body and the only protein amino acid that does not have chirality. Although most glycine is found in proteins, free glycine is found in body fluids as well as in plants.

Importance of Glycine (220)

Glycine is not considered an essential amino acid, i. e., the cells in the body can synthesize sufficient amounts of glycine to meet physiological requirements. However, glycine is of major importance in the synthesis of proteins, peptides, purines, adenosine triphosphate (ATP), nucleic acids, porphyrins, hemoglobin, glutathione, creatine, bile salts, one-carbon fragments, glucose, glycogen, and L-serine and other amino acids. Glycine is also a neurotransmitter in the central nervous system (CNS). Glycine and gamma-aminobutyric acid (GABA) are the major inhibitory neurotransmitters in the CNS. Recently, a glycine-gated chloride channel has been identified in neurophils that can attenuate increases in intracellular calcium ions and diminish oxidant damage mediated by these white blood cells. Thus, glycine may be a novel antioxidant.

Glycine and Reduction of Increased levels of cholesterol (160)

Glycine and Enlarged Prostate Gland (161, 162, 163)

Glycine and Diabetes Melitus (6, 141)

Reference

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  • 14) Di Pasquale, M, Amino Acids and Proteins for the Athlete, the Anabolic Edge, 1997.
  • 219)Gusev, Skvortsova et al., “Neuroprotective Effects of Glycine for Therapy of Acute Ischaemic Stroke”, Cerebrovasc Dis., Jan.-Feb.2000.
  • 220) Banay-Schwartz, Palkovitis, Lajtha, ” A Heterogeneous Distribution of Functionally Important Acids in Brain Areas of Adult and Aging Humans”. Neurochem. Res., 1993.
  • 221) Kasai, Kobayashi, Shimoda, “Stimulatory Effect of Glycine on Human Growth Hormone Secretion”, Metabolism, 1978.
  • 160) Katan, M. et al. reduction in casein-Induced hypercholesterolaemia and atherosclerosis in rabbits and rats by dietary Glycine, Arginine and Alanine, Atherosclerosist, 43: 381.
  • 161) Aito, K. Conservative treatment of Prostatic Hypertrophy, Hinyokika Kiyo, 18 (1): 41-44
  • 162) Shimaya, M. Double blind test of PPC for Prostatic Hyperplasia, Hinyokika Kiyo, 16 (5): 231-6
  • 163) Dumrau, F. BPH: Amino Acid Theraqpy for symptomatic relief, American Journal of Geriatrics, 10: 426-30
  • 6) Werbach, M. Nutritional Influences on Illness, Third Line Press, California
  • 141) Banarjee, S. Physiological role of dehydroascorbic acid, Indian Journal of Physiological Pharmacology, 21 (2): 85-93