Carnitin

Acetyl-i-carnitine (4) is marketed in Italy for dementia as of this writing it is also in Phase III clinical trials in the United States and Europe. In a double-blind, placebo-controUed clinical trial over a one-year period involving 130 patients with clinically diagnosed AD, a slower rate of deterioration in 13 of the 14 outcome measures was observed in the dmg-treated group (28). Earfler smaller scale pilot studies in demented patients had also shown some improvement of various behavioral and cognitive functions (29). 

Detoxifica.tlon. Detoxification systems in the human body often involve reactions that utilize sulfur-containing compounds. For example, reactions in which sulfate esters of potentially toxic compounds are formed, rendering these less toxic or nontoxic, are common as are acetylation reactions involving acetyl—SCoA (45). Another important compound is. Vadenosylmethionine [29908-03-0] (SAM), the active form of methionine. SAM acts as a methylating agent, eg, in detoxification reactions such as the methylation of pyridine derivatives, and in the formation of choline (qv), creatine [60-27-5] carnitine [461-06-3] and epinephrine [329-65-7] (50). 

Biochemical Functions. Ascorbic acid has various biochemical functions, involving, for example, coUagen synthesis, immune function, dmg metabohsm, folate metaboHsm, cholesterol cataboHsm, iron metaboHsm, and carnitine biosynthesis. Clear-cut evidence for its biochemical role is available only with respect to coUagen biosynthesis (hydroxylation of prolin and lysine). In addition, ascorbic acid can act as a reducing agent and as an effective antioxidant. Ascorbic acid also interferes with nitrosamine formation by reacting direcdy with nitrites, and consequently may potentially reduce cancer risk. 

Ascorbic acid is involved in carnitine biosynthesis. Carnitine (y-amino-P-hydroxybutyric acid, trimethylbetaine) (30) is a component of heart muscle, skeletal tissue, Uver and other tissues. It is involved in the transport of fatty acids into mitochondria, where they are oxidized to provide energy for the ceU and animal. It is synthesized in animals from lysine and methionine by two hydroxylases, both containing ferrous iron and L-ascorbic acid. Ascorbic acid donates electrons to the enzymes involved in the metabohsm of L-tyrosine, cholesterol, and histamine (128). 

Carnitine Carries Fatty Acyl Groups Across the Inner Mitochondrial Membrane... 

All of the other enzymes of the /3-oxidation pathway are located in the mitochondrial matrix. Short-chain fatty acids, as already mentioned, are transported into the matrix as free acids and form the acyl-CoA derivatives there. However, long-chain fatty acyl-CoA derivatives cannot be transported into the matrix directly. These long-chain derivatives must first be converted to acylearnitine derivatives, as shown in Figure 24.9. Carnitine acyltransferase I, located on the outer side of the inner mitochondrial membrane, catalyzes the formation of... 

FIGURE 24.9 The formation of acylcar-nitines and their transport across the inner mitochondrial membrane. The process involves the coordinated actions of carnitine acyltrans-ferases on both sides of the membrane and of a translocase that shuttles O-acylcarnitines across the membrane. 

What would be the consequences of a carnitine deficiency for fatty acid oxidation ... 

The dried product was dissolved in 46.5 cc of glacial acetic acid by heating on a boiling water bath. The insoluble matter is removed by filtering hot, and on cooling the mother liquor, crystals of carnitine hydrochloride separated out. The crystals were filtered, washed with 10 cc of ethanol, and dried. Recrystallizing 19.7 g of the crude carnitine with methanol, 17 g of the refined carnitine was obtained [MP 195°-198°C (decomposing point), yield 86%]. 

The overall yield of the refined carnitine through whole steps was about 74%. Carnitine thus prepared was an odorless, white, crystalline powder, having a strong acid taste. 

Endomethylene-A -tetrahydro benzaldehyde Cyclothiazide Epibromohydrin Carteolol Epichlorohydrin Acebutolol Atenolol Befunolol Betaxolol HCI Bufetrol Bunitrolol Bupranolol Carazolol Carnitine Celiprolol Colestipol Cromolyn sodium I ndenolol Mazindol Mepindolol Metoprolol tartrate Nadolol Nifuratel Oxprenolol Penbutolol Practolol Propafenone HCI Propranolol HCI Viloxazine HCI Xanthinol niacinate Epinephrine... 

F.3 What is the mass percentage composition of I-carnitine, C7HhN03, a compound that is taken as a dietary supplement to reduce muscle fatigue ... 

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