Acetyl-CoA carboxylase and citrate cleavage enzymein the rat mammary gland

Pj, Howanitz; Hr, Levy

doi:10.1016/0005-2760(65)90056-1

Cited by 45 publications

(16 citation statements)

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“…Similarly, the ratio of citrate to acetate incorporated into fatty acids in rat liver preparations is decreased tenfold by fasting and increased 100-fold by carbohydrate refeeding. Similar results were observed adipose tissue (166), and a large increase in the activity of the citrate cleavage enzyme accompanied lactation in the rat mammary gland (167). The concentration of citrate cleavage enzyme also varies in accord with its presumed role as a major source of acetyl units in lipid biosynthesis.…”

Section: Co~;trol Of Fatty Acid Metabolismsupporting

confidence: 62%

Lipid Metabolism

Olson¹

1966

Annu. Rev. Biochem.

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The malonyl-GoA pathway of the cytoplasm.-The synthesis of fatty acids in many living organisms is catalyzed by a cytoplasmic enzyme complex. These complexes, which contain at least six or seven different kinds of pro teins, are tightly bound together in yeast (1) and pigeon liver (2, 3) , but are readily dissociable in Clostridium kluyverii, E. coli (4), and in several plant systems (5, 6). Of the various fatty acid synthesizing complexes, the system from E. coli has been most extensively studied. Of predominant interest in these studies is the isolation and characterization of acyl carrier protein (ACP), which binds acyl intermediates during the formation of long chain fatty acids (1, 7, 8). ACP is heat stable, has 81 to 89 amino acids and con tains one free sulfhydryl group per mole, at which the acyl derivatives bind (9). ACP was first thought to contain cysteine (9), but later was shown to contain 2-mercaptoethylamine and an equivalent amount of fJ-alanine (10). These latter two compounds and pantoic acid are bound together as 4'-1 This review covers the period November 1964 through October 1965.2 Abbreviations used in formulae, or repeatedly in the text, are given below in alphabetical order: ACP (acyl carrier protein); ATPase (adenosine triph osphatase) ; CDP (cytidine diphosphate) ; CMP (cytidine monophosphate); DG (diglyceride); EFA (essential fatty acid) i FAD (flavin adenine dinucleotide) ; FM N (flavin mono nucleotide) i Gal (galactose) i GDP (guanosine dipho�phate); Gic (glucose); GTP (guanosine triphosphate) i Man (mannose) i MG (monoglyceride); GalNAc (N-acetyl galactosamine); GIcNAc (N -acetylglucosamine) i M urNAc (N-acetylmuramic add) i NAD (nicotinamide adenine dinucleotide) i NADH (reduced nicotinamide adenine dinucleotide) i NADP (nicotinamide adenine dinucleotide phosphate) ; NADPH (reduced nicotinamide adenine dinucleotide phosphate); NAN A (N -acetylneuraminic acid, sialic acid); OAA (oxaloacetic acid) i Pi (inorganic phosphate) i PG (prosta glandin) see Table II; PP (pyrophosphate); Pt.H, (2-amino-4-hydroxy-6-methyl tetrahydropteridine); PtJ -I.(rhamnose) ; sRNA (soluble ribonucleic acid); TCA (tricarboxylic acid cycle) i TDP (thymidine diphosphate); TG (triglyceride); UDP (uridine diphosphate). Fatty acids are often expressed in terms of the number of carbon atoms, number of double bonds and double bond position and isomer, e.g., linoleic acid is C18:2(9c, 12c), where c denotes cis and t indicates trans. R denotes the remaining portion of a given organic molecule which is not modified during the reaction shown. Amino acids are given con ventional three letter designations. R (rectus) and s (sinister) denote the absolute configuration of a carbon atom by the convention of Cahn, Ingold, & Prelog (1a).

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Section: Co~;trol Of Fatty Acid Metabolismsupporting

confidence: 62%

Lipid Metabolism

Olson¹

1966

Annu. Rev. Biochem.

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“…However, the 37-fold increase in acetyl-CoA synthetase activity from 30 days prepartum to 40 days postpartum noted in the cow (Table 3) is substantially greater than the 3-fold increase reported for rat mammary tissues during lactogenesis (Baldwin & Milligan, 1966). The relative increase in acetyl-CoA carboxylase activity in cow mammary tissue pre and post partum was greater than increases reported for mouse (Jones, 1972) and rabbit (Hartmann & Jones, 1970) mammary gland, but approximated to the change in rat mammary tissue (Howanitz & Levy, 1965).…”

Section: Discussionmentioning

confidence: 53%

“…Acetyl-CoA carboxylase has been postulated as the rate-limiting enzyme of fatty acid synthesis (Ganguly, 1960;Numa et al, 1965;Howanitz & Levy, 1965;1973Smith et al, 1966. In general this conclusion was based on the facts that the activity of acetyl-CoA carboxylase (as assayed in vitro) was lower than other enzymes involved in lipogenesis, and that acetyl-CoA carboxylase possessed numerous kinetic properties characteristic of regulatory enzymes.…”

Section: Discussionmentioning

confidence: 99%

Metabolic adaptations during lactogenesis. Fatty acid and lactose synthesis in cow mammary tissue

Mellenberger

Bauman

Nelson

1973

Biochemical Journal

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1. Mammary-tissue biopsies were obtained from multiparous cows at 30 and 7 days pre partum and 7 and 40 days post partum. Investigations of the effect of lactogenesis on fatty acid and lactose synthesis involved measurements of biosynthetic capacity (tissue-slice incubations in vitro) and activities of relevant enzymes. 2. Fatty acid synthesis from acetate increased over 20-fold from 30 days pre partum to 40 days post partum. Changes in the lipogenic capacity of mammary-tissue slices more closely paralleled increases in the activities of acetyl-CoA carboxylase (EC 6.4.1.2) and acetyl-CoA synthetase (EC 6.2.1.1) than of other enzymes involved in acetate incorporation into fatty acids or in NADPH generation. 3. Lactose biosynthesis by mammary-tissue slices, lactose synthetase activity (EC 2.4.1.22) and alpha-lactalbumin concentration were all negligible at 30 days pre partum but increased 2.5-4-fold between 7 days pre partum and 40 days post partum. Phosphoglucomutase (EC 2.7.5.1), UDP-glucose pyrophosphorylase (EC 2.7.7.9) and UDP-glucose 4-epimerase (EC 5.1.3.2) had substantial activities at 30 days pre partum and increased less dramatically during lactogenesis. 4. Results are consistent with acetyl-CoA carboxylase and perhaps acetyl-CoA synthetase representing the regulatory enzyme(s) in fatty acid synthesis, with lactose synthetase (alpha-lactalbumin) serving a similar function in lactose biosynthesis.

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“…The precise time at which milk-specific fatty acid synthesis begins is not known, but increased activities of a number of lipogenic enzymes after parturition have often been reported (e.g. Howanitz & Levy, 1965;Gumaa et al, 1973); it has also been shown that the increase in acetyl-CoA carboxylase activity is due to an increase in the concentration of enzyme (Mackall & Lane, 1977).…”

Section: Initiation Of Fatty Acid Synthesis In Rat Mammary Glandsmentioning

confidence: 99%

Initiation of fatty acid synthesis in rat mammary glands

Martyn¹,

Hansen²

1980

Biochemical Journal

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The rate of fatty acid synthesis from [6-14C]glucose in mammary tissue remained low until parturition at 22 days of gestation and increased 10-fold at 1 day post partum. Administration of progesterone on days 20 and 21 or removal of pups at parturition abolished this increase. In the latter case, administration of prolactin, corticosterone or oxytocin had no stimulatory effect; tissue from suckled glands in which the ducts had been ligated at parturition also showed no increased rate in 24 h. Foetoplacentectomy on day 18 did not stimulate fatty acid synthesis but subsequent suckling by foster pups did. Whereas lactose synthesis is initiated by withdrawal of progesterone from the circulation, a further stimulus related to removal of milk by suckling is required to initiate fatty acid synthesis.

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Acetyl-CoA carboxylase and citrate cleavage enzymein the rat mammary gland

Cited by 45 publications

References 9 publications

Lipid Metabolism

Lipid Metabolism

Metabolic adaptations during lactogenesis. Fatty acid and lactose synthesis in cow mammary tissue

Initiation of fatty acid synthesis in rat mammary glands

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