METHYLCOBALAMIN by Ray Sahelian, M.D. Cobalamin information

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METHYLCOBALAMIN by Ray Sahelian, M.D. Cobalamin information

 

Methylcobalamin is one of the two coenzyme forms of vitamin B12

(cyanocobalamin). Vitamin B12 plays an important role in red blood

cells, prevention and treatment of anemia, methylation reactions,

and immune system regulation.

Evidence indicates methylcobalamin has

some metabolic and therapeutic applications not shared by the other

forms of vitamin B12.

 

Simple Methylcobalamin biochemistry

 

Methylcobalamin is the active form of vitamin B12 that acts as a

cofactor for methionine synthase in the conversion of homocysteine

to methionine, thus lowering blood levels of homocysteine.

 

Methylcobalamin acts as a methyl donor and participates in the

synthesis of SAM-e (S-adenosylmethionine), a nutrient that has

powerful mood elevating properties.

 

Vitamin B-12 Complex, 5 mg

60 Tablets

Source Naturals

 

 

 

• Methylcobalamin & Adenosylcobalamin

• Dietary Supplement

 

Advanced B-12 Complex combines the two active, coenzymated forms of

vitamin B-12 - methylcobalamin and adenosylcobalamin (dibencozide) -

with folic acid. Vitamin B-12 is required for normal growth, cell

reproduction, myelin and nucleoprotein synthesis, and the formation

of red blood cells. Coenzyme supplementation bypasses the body's

need to synthesize the active forms of vitamin B-12 from

cyanocobalamin.

 

Methylcobalamin Supplement Facts:

Serving Size: 1 Tablet

Servings per Bottle: 60

 

Amount Per Tablet

Folate - 400 mcg - 100%DV*

(as folic acid)

Vitamin B12 - 5,000 mcg - 84,440%DV*

(as methylcobalamin - 3mg and dibencozide [adenosylcobalamin]

2mg) 1 mg = 1,000 mcg

 

Suggested Use: One methylcobalamin tablet 2 or 3 times a week. Place

tablet under the tongue and allow to dissolve slowly, altering its

position to avoid prolonged contact with the same area.

 

* Methylcobalamin daily value not established

 

 

Mind Power Rx with Methylcobalamin - Formulated by Ray Sahelian, M.D.

 

 

Mind Power Rx with Methylcobalamin is a sophisticated cognitive

formula. It combines a delicate balance of brain circulation agents

and neurotransmitter precursors with powerful natural brain

chemicals that support:

 

• Memory and Mood

• Mental clarity

• Concentration

• Alertness & Focus

 

Mind Power Rx has 90 mcg of methylcobalamin per 3 capsules

 

The herbs in Mind Power Rx include: Ashwagandha, Bacopa, Fo-Ti,

Ginkgo biloba, Ginseng, Mucuna pruriens, and Reishi. The nutrients

and vitamins in Mind Power Rx include Acetyl-l-carnitine, Carnitine,

Carnosine, Choline, DMAE, Inositol, Methylcobalamin, Pantothenic

acid, Trimethylglycine, Tyrosine, and Vinpocetine.

 

 

Clinical Uses of Methylcobalamin

 

Methylcobalamin supplements increase alertness and body temperature.

Methylcobalamin may slightly help those with diabetic neuropathy. A

better nutrient for this condition is Lipoic Acid.

Methylcobalamin has been found to be helpful in Bell's palsy.

However, I don't have personal experience to determine whether

methylcobalamin given in a doctor's office to actual patients with

Bell's palsy really helps or not.

Methylcobalamin taken orally is effective in the treatment of

pernicious anemia, says a Japanese study.

Methylcobalamin may inhibit the ototoxic (hearing damage) side

effects of the antibiotic gentamicin.

 

Cobalamin and Methylcobalamin Biochemistry

 

The B12 or cobalamin coenzymes are complex macrocycles whose

reactivity is associated with a unique cobalt-carbon bond. The two

biologically active forms are methylcobalamin and AdoCbl and their

closely related cobamide forms. Methylcobalamin participates as the

intermediate carrier of activated methyl groups. During the

catalytic cycle the coenzyme shuttles between methylcobalamin and

the highly nucleophilic cob(I)alamin form.

Examples of

methylcobalamin -dependent enzymes include methionine synthase and

Me-H4-MPT: coenzyme M methyl transferase. AdoCbl functions as a

source of carbon-based free radicals that are unmasked by homolysis

of the coenzyme's cobalt-carbon bond. The free radicals are

subsequently used to remove non-acid hydrogen atoms from substrates

to facilitate a variety of reactions involving cleavage of carbon-

carbon, carbon-oxygen and carbon-nitrogen bonds.

 

Dibencozide

Dibencozide is an active coenzyme form of vitamin B-12.

It is

required for processing branched chain amino acids through the Krebs

cycle.

 

Cobalamin

Vitamin B12, or cobalamin, is one of the most structurally complex

small molecules made in Nature.

 

Adenosyltransferase converts

cobalamin to coenzyme B(12).

 

Four cobalamines (methyl-, hydroxy-, adenosyl- and

cyancobalamines) are considered as natural forms of vitamin B12 in

human and animal tissues. Methyl- and adenosylcobalamines are the

coenzymes of more than 10 enzymes, catalyzing important reactions of

lipid, carbohydrate and protein metabolism. The four natural forms

of vitamin B12 are interconverted in presence of corresponding

enzymatic systems.

 

Content of individual forms of cobalamines and of

corresponding coenzymes depends on the function of enzymatic systems

involved in their synthesis as well as on the enzymes, which use

these derivatives as coenzymes. Spectra of cobalamines in human and

animal bodies are dynamic systems, distinctly and specifically

responding to various effects.

 

Adenosylcobalamin

The biosynthetic route to adenosylcobalamin from its five-carbon

precursor, 5-aminolaevulinic acid, can be divided into three

sections: (1) the biosynthesis of uroporphyrinogen III from 5-

aminolaevulinic acid, which is common to both pathways; (2) the

conversion of uroporphyrinogen III into the ring-contracted,

deacylated intermediate precorrin 6 or cobalt-precorrin 6, which

includes the primary differences between the two pathways; and (3)

the transformation of this intermediate to form adenosylcobalamin.

 

Methylcobalamin Research Update

Oral supplements of vitamin B12 appear to correct vitamin B12

deficiencies as well as B12 injections. However, in order to correct

a deficiency, oral doses need to contain more than 200 times the

recommended daily allowance (RDA) of vitamin B12.

 

Study author Dr.

Lisette C. P. G. M. de Groot of Wageningen University in the

Netherlands explained that most people develop vitamin B12

deficiencies as a result of " malabsorption, " in which their bodies

become unable to extract vitamin B12 from food. To investigate

whether an oral dose of vitamin

B12 works, as well, they tested various daily doses of oral vitamin

B12 supplements in 120 people aged 70 and older. They found that

daily oral doses of 647 to 1032 micrograms of vitamin B12 appeared

to correct the deficiency.

 

The current RDA for vitamin B12 is 3

micrograms per day. SOURCE: Archives of Internal Medicine, May 23,

2005.

 

Mothers with low levels of vitamin B12 in their blood are at

increased risk of having an infant with spina bifida -- a birth

defect in which the spinal cord fails to form properly. Based on

previous research, pregnancy guidelines recommend that women consume

enough folic acid to reduce the risk of spina bifida and related

problems. The new findings suggest that these guidelines should also

include recommendations about vitamin B12.

 

The many faces of vitamin B12: catalysis by cobalamin-dependent

enzymes.

Annu Rev Biochem. 2003;72:209-47.

 

Vitamin B12 is a complex organometallic cofactor associated with

three subfamilies of enzymes: the adenosylcobalamin-dependent

isomerases, the methylcobalamin -dependent methyltransferases, and

the dehalogenases. Different chemical aspects of the cofactor are

exploited during catalysis by the isomerases and the

methyltransferases. Thus, the cobalt-carbon bond ruptures

homolytically in the isomerases, whereas it is cleaved

heterolytically in the methyltransferases. The reaction mechanism of

the dehalogenases, the most recently discovered class of B12

enzymes, is poorly understood. Over the past decade our

understanding of the reaction mechanisms of B12 enzymes has been

greatly enhanced by the availability of large amounts of enzyme that

have afforded detailed structure-function studies, and these recent

advances are the subject of this review.

 

Cobalamin-dependent methyltransferases.

Acc Chem Res. 2001 Aug;34(8):681-9.

 

Cobalamin cofactors play critical roles in radical-catalyzed

rearrangements and in methyl transfers. This Account focuses on the

role of methylcobalamin and its structural homologues, the

methylcorrinoids, as intermediaries in methyl transfer reactions,

and particularly on the reaction catalyzed by cobalamin-dependent

methionine synthase. In these methyl transfer reactions, the cobalt

(I) form of the cofactor serves as the methyl acceptor. Biological

methyl donors to cobalamin include N5-methyltetrahydrofolate, other

methylamines, methanol, aromatic methyl ethers, acetate, and

dimethyl sulfide. The challenge for chemists is to determine the

enzymatic mechanisms for activation of these unreactive methyl

donors and to mimic these amazing biological reactions.

 

Effects of vitamin B12 on performance and circadian rhythm in normal

subjects.

Neuropsychopharmacology. 1996 Nov;15(5):456-64.

 

This preliminary study investigates effects of methyl- and

cyanocobalamin on circadian rhythms, well-being, alertness, and

concentration in healthy subjects. Six women (mean age 35 years) and

14 men (mean age 37 years) were randomly assigned to treatment for

14 days with 3 mg cyano-(CB12) or methylcobalamin (MB12) after 9

days of pre-treatment observation. Levels in the CB12 group

increased rapidly in the first, then slowly in the second treatment

week, whereas increase in the MB12 group was linear.

Urinary aMT6s

excretion was reduced by both forms of vitamin B12 over 24 hours

with a significant decrease between 0700-1100 hours, whereas urinary

excretion of potassium was significantly increased between 0700-1100

hours. Activity from 2300-0700 hours increased significantly under

both forms of vitamin B12. Sleep time was significantly reduced

under MB12 intake.

 

In this group the change in the visual analogue

scales items " sleep quality, " " concentration, " and " feeling

refreshed " between pretreatment and the first week of treatment

showed significant correlations with vitamin B12 plasma levels.

Cortisol excretion and temperature were not affected by either

medication. We conclude that vitamin B12 exerts a direct influence

on melatonin. Only MB12 has a positive psychotropic alerting effect

with a distribution of the sleep-wake cycle toward sleep reduction.

 

Coenzyme B12 (cobalamin)-dependent enzymes.

Essays Biochem. 1999;34:139-54.

 

The B12 or cobalamin coenzymes are complex macrocycles whose

reactivity is associated with a unique cobalt-carbon bond. The two

biologically active forms are methylcobalamin and AdoCbl and their

closely related cobamide forms.

 

Methylcobalamin participates as the

intermediate carrier of activated methyl groups. During the

catalytic cycle the coenzyme shuttles between methylcobalamin and

the highly nucleophilic cob(I)alamin form.

Examples of

methylcobalamin -dependent enzymes include methionine synthase and

Me-H4-MPT: coenzyme M methyl transferase.

 

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