MAMMALIAN METHYLMALONYL ISOMERASE AND VITAMIN B
            <sub>12</sub>
            COENZYMES

Lengyel, Péter; Mazumder, Rajarshi; Ochoa, Severo

doi:10.1073/pnas.46.10.1312

Cited by 113 publications

(32 citation statements)

References 16 publications

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“…The presence of these mechanisms supports the concept that Cbl analogues of microorganismal origin are inert (1,6,7) or even toxic (7) for animals.…”

Section: Introductionsupporting

confidence: 69%

Presence and formation of cobalamin analogues in multivitamin-mineral pills.

Kondo¹,

Binder²,

Kolhouse³

et al. 1982

J. Clin. Invest.

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A B S T R A C T Because the origin of cobalamin (vitamin B12) analogues in animal chows and animal and human blood and tissues is unknown, we investigated the possibility that multivitamin interactions might convert cobalamin to cobalamin analogues. We homogenized three popular multivitamin-mineral pills in water, incubated them at 37°C for 2 h, and isolated the cobalamin. Using paper chromatography we observed that 20-90% of the cobalamin was present as cobalamin analogues. Studies using cobalamin showed that these analogues were formed due to the concerted action of vitamin C, thiamine, and copper on CN-cobalamin. These cobalamin analogues are absorbed from the gastrointestinal tract of mice and either fail to stimulate or actually inhibit cobalamindependent enzymes when injected parenterally.We conclude that CN-cobalamin can be converted to potentially harmful cobalamin analogues by multivitamin-mineral interactions and that these interactions may be responsible for the presence of cobalamin analogues in animal chows and animal and human blood and tissues.

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“…The presence of these mechanisms supports the concept that Cbl analogues of microorganismal origin are inert (1,6,7) or even toxic (7) for animals.…”

Section: Introductionsupporting

confidence: 69%

Presence and formation of cobalamin analogues in multivitamin-mineral pills.

Kondo¹,

Binder²,

Kolhouse³

et al. 1982

J. Clin. Invest.

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“…The present communication definitely implicates MM-mutase activity in both by the addition of 300 ul water, and the vessels were immersed in a boiling water bath for 15 min. 100 mg NaCl, 120 jug each of methylmalonic acid and succinate, and 2 drops of 12 N H2S04 were added.…”

mentioning

confidence: 59%

Congenital Methylmalonic Acidemia: Enzymatic Evidence for Two Forms of the Disease

Morrow

Barness

Cardinale

et al. 1969

Proc. Natl. Acad. Sci. U.S.A.

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Abstract.-Methylmalonic acidemia is an inherited metabolic disorder thus far found in children and characterized by the excessive excretion of methylmalonate in the urine. Typically these children exhibit vomiting, lethargy, ketoacidosis, and failure to grow. Many of the patients are mentally retarded and die early in life. Two variants of this disease are known. In one, the administration of vitamin B12 will reverse or prevent these clinical findings, whereas in a second variant vitamin B12 therapy is of no value.This paper presents the first enzymatic evidence (obtained with cell-free liver extracts) that bears on two important aspects of the disease. It has been found that methylmalonylCoA carbonylmutase activity is essentially absent in the livers of patients suffering from one variant (vitamin B12-unresponsive) of the disease. Secondly, it has been found that the livers of patients with the second variant (vitamin BH2-responsive) of the disease show normal enzymatic behavior in the presence of the coenzyme form of vitamin B,2, but are identical to the vitamin B,2-unresponsive variant in the absence of the added coenzyme. Thus the enzyme studies fully support the clinical observations that two types of this disease exist.Introduction.-Two variants of inherited methylmalonic acidemia have been described since the original report of this inborn error of metabolism by Oberholzer et al. ' The metabolic pathway involved is the conversion of propionate to succinate, one step of which requires the cobamide coenzyme form of vitamin

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“…The fact that some naturally occurring analogues are inactive (17) (23) in which CN-Cbl was incubated at 65°C for 6 min in concentrated HC1. The sample was diluted with 10 vol of H20, and the chloride was removed by application to a 2.0 x 30-cm column of Dowex AG 1 x 8 acetate, equilibrated in H20 at 4°C.…”

mentioning

confidence: 99%