The efficiency and safety evaluation of hemoglobin hydrolysate as a non-heme iron fortifier

Hemoglobin hydrolysate is derived from the enzymatic degradation of hemoglobin.This work aimed to evaluate whether hemoglobin hydrolysate promotes the absorption of non-heme iron and the safety of absorbed iron in mice by analyzing the iron binding content,iron circulation,and liver homeostasis.We found that hemoglobin hydrolysate promoted the absorption of non-heme iron with high efficiency in duodenum by spontaneously binding non-heme iron during digestion,and increased hepatic iron content by up-regulating divalent metal transporter 1,zinc transporter 14,but hepatic iron content only increased at 3 weeks.Duodenal iron entered the blood through ferroportin without restriction at 3 weeks,and excessive iron entered the liver and then affected the hepatocyte membranes permeability and lipid synthesis through oxidative stress.With the prolongation of dietary intervention,the up-regulated hepcidin acted on the ferroportin to restrict excess iron from entering the blood,and then the hepatic homeostasis recovered.In addition,hemoglobin hydrolysate enhanced the hepatic antioxidant capacity.Taken together,hemoglobin hydrolysate has a strong ability to promote the absorption of non-heme iron in vivo,and the absorbed iron is relatively safe due to the regulation of hepcidin.

Effect of Pork Meat pH on Iron Release from Heme Molecule during Cooking

This study investigated the relationship between the level of iron chemical forms and the initial raw meat pH values during cooking, including the effect of the sodium nitrite presence. The pH value, the heme iron （HI） and non-heme iron （NHI） concentrations were measured on one ground portion of five loin, five masseter, five semimembranosus, five neck muscles and five shoulder muscles. Afterwards, all raw meats were halved and mixed with NaCl （2%）, ascorbic acid （0.05%） and 0 mg/kg of sodium nitrite （mix1） or 150 mg/kg of sodium nitrite （mix2）. Both mixes were divided into 50 g-portions, vacuum packed in cryovac bags and cooked in thermostatic bath up to F （10, 71 ℃） = 30 minutes at the core. The NHI and HI concentrations were determined both on the cooked meats and on the juice lost during cooking. The cooking process caused the release of NHl and H1 on all cooked sample juices. The HI overall percentage was significantly lower than raw meat one （P 〈 0.005） and the NHI significantly higher （P 〈 0.005） in all cooked mix 1. The raw and cooked HI percentage variances depended on the pork meat pH values （ra = 0.70）. The overall HI percentage was unchanged respect to raw meats on cooked mix 2, while the NHI amount was not quantitatively estimated. These results emphasized the role of sodium nitrite on tying up NHI in the cooked meats and safeguarding the oxidative stability of cooked meat products.

Nonheme Iron-Catalyzed Enantioselective cis-Dihydroxylation of Aliphatic Acrylates as Mimics of Rieske Dioxygenases

Enantioselective cis-dihydroxylation of alkenes represents an ideal route to synthesize enantioenriched syn-2,3-dihydroxy esters that are important structural motifs in numerous biologically and pharmaceutically relevant molecules.Bioinspired nonheme iron-catalyzed enantioselective cis-dihydroxylation meets the requirement of the modern synthetic chemistry from the atomic economy,green chemistry,and sustainable development perspectives.However,nonheme iron-catalyzed enantioselective cis-dihydroxylation is much underdeveloped because of the formidable challenges of controlling chemo-and enantioselectivities and product selectivity caused by the competitive epoxidation,cis-dihydroxylation,and overoxidation reactions.Herein,we disclose the fabrication of a biologically inspired nonheme iron complex-catalyzed enantioselective cis-dihydroxylation of multisubstituted acrylates using hydrogen peroxide(H_(2)O_(2))as the terminal oxidant by controlling the non-ligating or weakly ligating counterions of iron(Ⅱ)complexes,demonstrating a dramatic counteranion effect on the enantioselective cisdihydroxylation of olefins by H_(2)O_(2) catalyzed by nonheme iron complexes.A range of structurally disparate alkenes were transformed to the corresponding syn-2,3-dihydroxy esters in practically useful yields with exquisite chemo-and enantioselectivities(up to 99% ee).Given the mild and benign nature of this biologically inspired oxidation system as well as the ubiquity and synthetic utility of enantioenriched syn-2,3-dihydroxy esters as pharmaceuticals candidates and natural products,we expect that this strategy could serve as a promising complement to the well-known Sharpless asymmetric dihydroxylation,which is the chemical reaction of an alkene with OsO_(4) to produce a vicinal diol.

细菌Rieske型非血红素铁加氧酶研究进展

细菌Rieske型非血红素铁加氧酶是催化芳香化合物好氧降解第一步反应的酶,能够激发好氧环境下大量芳香或取代芳香化合物的生物降解,同时还可作为有机化合物的合成子.这是一类新型且丰富的酶资源,在受污环境的生物修复方面有着巨大的潜力,并且符合“绿色化学”的要求.本文综述了该类酶的分类、晶体结构、作用机理及其基因改造等最新研究进展.

芳香化合物羟基化酶研究进展

芳香族化合物的选择性羟基化是合成化学中最具挑战性的化学反应之一,特别是由于近年来羟基芳香族化合物在医学上作为前驱体使用,使其越来越受到重视.通过单一酶或者整个微生物细胞进行的生物催化氧传递,是完成芳香化合物选择性羟基化反应的一种有效方式,不仅在受污染环境的生物修复中作用重大,而且还可以替代并拓宽传统的化工合成工艺,广泛用于化工中间体的生产,这使得芳香化合物羟化酶成为重要的工业用酶之一.本文综述了芳香化合物羟基化酶的种类、作用机理及工业应用等方面的最新研究进展.

细菌Rieske非血红素铁环羟化酶在多环芳烃降解中的研究进展

多环芳烃是一种常见的持久性有机污染物,因具有致癌、致突变等毒性而被广泛关注。其微生物降解过程通常由羟化起始,随后脱氢、开环、一步步去除支链,最终进入三羧酸循环。Rieske非血红素铁环羟化酶(Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases,RHOs,又称aromatic ring-hydroxylating dioxygenases)或细胞色素P450氧化酶负责将羟基加成到多环芳烃环上,将疏水性的多环芳烃转化为亲水性的衍生物,这一过程是多环芳烃降解转化的起始步骤,也是关键步骤和限速步骤之一。文中主要介绍RHOs的分布、底物特异性、底物识别机制以及研究RHOs与多环芳烃的一些技术和方法等,并对RHOs在环境修复技术中的潜在应用进行了展望。