The Binding of Pyridoxal 5′‐Phosphate to Human Serum Albumin

Fonda, Margaret L.; Trauss, Christiane; Guempel, Ulrike M.

doi:10.1111/j.1749-6632.1990.tb28082.x

Cited by 8 publications

(3 citation statements)

References 3 publications

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“…Normal plasma concentrations of endogenous PLP are low, ranging from 50 to 300 n m [7]. In general, pyridoxal is rather the ultimate transport form into the cells than plasma PLP, which is not absorbed directly by tissues.…”

Section: Introductionmentioning

confidence: 99%

Involvement of P2Y receptors in pyridoxal‐5′‐phosphate‐induced cardiac preconditioning

Millart¹,

Alouane

Oszust

et al. 2009

Fundamemntal Clinical Pharma

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Using an isolated non‐working rat heart model, this study investigated the mechanisms of pharmacological pre‐conditioning (PC) induced by P2Y receptor stimulation with pyridoxal‐5′‐phosphate (PLP). After 6‐hydroxydopamine pretreatment and a 15‐min stabilization period, isolated rat hearts were perfused for 25 min then subjected to 40 min of global ischemia and 30 min of reperfusion (I/R); exposed for 15 min to 0.05 μm PLP bracketed for 25 min with broad‐spectrum P2 antagonists (suramin or PPADS) or with more specific P2Y antagonists (AMPαS or MRS2578), 1 μm each, followed by a 5‐min PLP‐free perfusion before I/R; treated during 25 min with either glybenclamide (GLY, 1 μm), 5‐hydroxydecanoic acid (5‐HD, 100 μm), U73122 (0.5 μm), H89 (1 μm), or KN93 (1 μm), with an infusion starting 5 min before PLP. The main endpoints were the rate–pressure product (RPP), creatine kinase (CK) release and area necrosis. Recovery of RPP, measured 5 min after reperfusion, was rapidly improved by PLP, blocked by the P2 antagonists, and decreased with the different inhibitors. Fifteen minutes after the end of ischemia, CK release reached maximal values in all groups. PLP provided significant protection, whereas the P2 antagonists, 5‐HD, a mitochondrial selective KATP antagonist and GLY a non‐selective KATP channel blocker, suppressed the protective effect on myocardial injury. The suppression of the cardioprotective effects of PLP by AMPαS, the PKA inhibitor (H89), and phospholipase C blocker (U73122) is in agreement with the P2Y11 receptor as a receptor for PLP‐induced PC. The suppression of the cardioprotective effects of PLP by MRS2578 and U73122 is in agreement with the P2Y6 receptor as a receptor for PLP‐induced PC. Pre‐ischemic exposure to nanomolar concentrations of PLP is protective against I/R. P2Y11 and P2Y6 represents the most likely candidate receptors for PLP‐induced cardiac PC.

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Section: Introductionmentioning

confidence: 99%

Involvement of P2Y receptors in pyridoxal‐5′‐phosphate‐induced cardiac preconditioning

Millart¹,

Alouane

Oszust

et al. 2009

Fundamemntal Clinical Pharma

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“…The plasma PLP concentrations have been suggested as the most valid indicator to assess vitamin B6 nutritional status (1) because a PLP-albumin complex is released from the liver to the blood when the capacity of liver vitamin B6 stores is saturated (24). The cut-off value is 30 nmol/L (14).…”

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confidence: 99%

Changes in Plasma Pyridoxal 5'-Phosphate Concentration during Pregnancy Stages in Japanese Women

Shibata

Tachiki

Mukaeda

et al. 2013

J Nutr Sci Vitaminol

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Most Japanese women do not consume the estimated average requirement of vitamin B6 (1.7 mg/d) during pregnancy. Nevertheless, these deficiencies are not reported. We investigated a nutritional biomarker of vitamin B6 in pregnant Japanese women as well as their vitamin B6 intakes. Vitamin B6 intakes in the first, second, and third trimesters of pregnancy, and 1 mo after delivery were 0.79±0.61 (n=56), 0.81±0.29 (n=71), 0.90±0.35 (n=92), and 1.00±0.31 (n=44) mg/d, respectively. Plasma pyridoxal 5'-phosphate (PLP) concentrations in the first, second, and third trimesters of pregnancy, and 1 mo after delivery were 57.1±27.6 (n=56), 23.3±16.7 (n=71), 18.3±12.5 (n=92), and 43.9±33.4 (n=44) nmol/L, respectively. The plasma concentrations significantly decreased in the second and third trimesters of pregnancy compared to values from the first trimester (p<0.05), and these concentrations returned to the values of the first trimester of pregnancy 1 mo after birth.

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“…The metabolically active PLP that formed in the liver is either utilized directly or released into the circulation as a PLP-albumin complex (Bender 1992). In plasma, PLP is the primary form of vitamin B-6, predominantly as a PLP-albumin complex (Fonda et al 1991).…”

Section: Absorption Transport and Metabolismmentioning

confidence: 99%

Vitamin B-6 status of middle aged women consuming soymilk versus cow's milk

Ya-na¹

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Vitamin B-6 (B-6), an essential nutrient whose coenzyme form pyridoxal 5'-phosphate (PLP) is required by over 100 enzymes, is involved in various metabolic processes including glycogenolysis, niacin synthesis, lipid metabolism, erythrocyte function, nervous system function, hormone modulation, immune function, and one-carbon metabolism. Pyridoxine glucoside (PNG), a less bioavailable form compared with other forms of B-6, is present in plant foods and absent in animal foods. With the recognition of health effects of soy, such as its cholesterol-lowering effect, there has been an increase in soyfoods consumption. Middle aged women frequently have marginal intakes of B-6, and many drink soymilk for its purported benefit in relieving menopausal symptoms. Although the PNG content of soymilk has not been reported, PNG content of other soyfoods ranges from 57-67% of the total B-6. The effect of substituting soymilk for cow's milk on B-6 status was examined in middle aged women (aged 36-52 y; n = 16). The study employed a crossover design: a 14-d adjustment period followed by a 28-d experimental period, during which half the subjects consumed 4 cups of cow's milk and half consumed 4 cups of soymilk per day; a 14-d washout period and a second 28-d experimental period when subjects switched to the other milk. Participants followed aself-selected B-6 restricted diet (~1 mg/d) throughout the study by following a list of prohibited or restricted foods. Three consecutive 24-h urine samples were collected and fasting blood was drawn every two weeks. Methionine loads (0.1 g/kg body weight) were given at the end of each experimental period. Plasma PLP, 4-pyridoxic acid (4-PA), urinary 4-PA, and pre-and postload plasma homocysteine were determined by HPLC analysis. Using crossover ANOVA tests, mean plasma 4-PA (P = 0.001), and urinary 4-PA-to-creatinine ratio (P < 0.001) were significantly lower when soymilk was consumed. There was no evidence that the mean plasma PLP (P = 0.107) and the increase in mean plasma total homocysteine concentrations after a methionine load (P = 0.316} were different between the cow's milk and soymilk treatments. We may have reported significant effects during the soymilk versus cow's milk treatment if the study period was longer (>28 d), the diets more rigidly controlled, and our sample size was larger (n > 16) regarding these two measures. These results suggest that substituting soymilk for cow's milk has an adverse

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The Binding of Pyridoxal 5′‐Phosphate to Human Serum Albumin

Cited by 8 publications

References 3 publications

Involvement of P2Y receptors in pyridoxal‐5′‐phosphate‐induced cardiac preconditioning

Involvement of P2Y receptors in pyridoxal‐5′‐phosphate‐induced cardiac preconditioning

Changes in Plasma Pyridoxal 5'-Phosphate Concentration during Pregnancy Stages in Japanese Women

Vitamin B-6 status of middle aged women consuming soymilk versus cow's milk

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