VITAMIN Blz AND TRANSMETHYLATION IN PIG, CHICK, AND RAT LIVER HOMOGENATES*
نویسندگان
چکیده
The interrelationship of the requirement of choline, methionine, betaine, vitamin B12, and folic acid has been the subject of many recent investigations (2-5). That vitamin Blz functions in the intermediary metabolism of l-carbon units is also well recognized (1, 6-20, 21). However, while there have been several reports concerning the effect of the vitamin in viva and in vitro systems, the precise role of the vitamin in transmethylation reactions, in methyl synthesis, or in both, is still controversial. In earlier investigations from this laboratory (22, 23) it was shown that, on a synthetic milk diet containing 1.6 per cent methionine, the baby pig exhibited no demonstrable dietary choline requirement. Since a clear cut vitamin Blz deficiency can readily be produced in the baby pig (24, 25), the effect of this deficiency on the synthesis of choline in viva by transmethylation from methionine was studied. It was clearly shown that the vitamin was not involved in this direct transmethylation (19). The present experiments describe the formation in vitro of creatine and methionine in liver homogenates of these animals. Transmethylation reactions with normal and vitamin Blz-deficient chick and rat liver homogenates have also been examined.
منابع مشابه
Vitamin B12 and transmethylation in pig, chick, and rat liver homogenates.
The interrelationship of the requirement of choline, methionine, betaine, vitamin B12, and folic acid has been the subject of many recent investigations (2-5). That vitamin Blz functions in the intermediary metabolism of l-carbon units is also well recognized (1, 6-20, 21). However, while there have been several reports concerning the effect of the vitamin in viva and in vitro systems, the prec...
متن کاملGains from diversification on convex combinations: A majorization and stochastic dominance approach
By incorporating both majorization theory and stochastic dominance theory, this paper presents a general theory and a unifying framework for determining the diversification preferences of risk-averse investors and conditions under which they would unanimously judge a particular asset to be superior. In particular, we develop a theory for comparing the preferences of different convex combination...
متن کاملImproved immunogenicity of tetanus toxoid by Brucella abortus S19 LPS adjuvant.
BACKGROUND Adjuvants are used to increase the immunogenicity of new generation vaccines, especially those based on recombinant proteins. Despite immunostimulatory properties, the use of bacterial lipopolysaccharide (LPS) as an adjuvant has been hampered due to its toxicity and pyrogenicity. Brucella abortus LPS is less toxic and has no pyrogenic properties compared to LPS from other gram negati...
متن کاملSteady electrodiffusion in hydrogel-colloid composites: macroscale properties from microscale electrokinetics.
A rigorous microscale electrokinetic model for hydrogel-colloid composites is adopted to compute macroscale profiles of electrolyte concentration, electrostatic potential, and hydrostatic pressure across membranes that separate electrolytes with different concentrations. The membranes are uncharged polymeric hydrogels in which charged spherical colloidal particles are immobilized and randomly d...
متن کاملPerturbative Analysis of Dynamical Localisation
In this paper we extend previous results on convergent perturbative solutions of the Schrödinger equation of a class of periodically timedependent two-level systems. The situation treated here is particularly suited for the investigation of two-level systems exhibiting the phenomenon of (approximate) dynamical localisation. We also present a convergent perturbative expansion for the secular fre...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2003