What are the effects of lactoferrin

Lactoferrin (LF) is an important non-heme iron-binding glycoprotein in milk, with a molecular mass of 70-80 kDa, composed of a single polypeptide chain and 2 to 4 polysaccharide side chains. Expression and secretion by breast epithelial cells. Lactoferrin was first discovered in animal milk by Sorensen in 1939, and was first isolated from cow milk by Groves. Because the complex formed by combining with iron is red, it is called "globin". In 1961, Blanc and Isliker officially named this protein isolated from human milk as lactoferrin.

Introduction

A non-heme iron-binding glycoprotein in milk

Molecular mass

70～80 kDa

composition

A single polypeptide chain and 2～4 polysaccharide side chains

Lactoferrin distribution

Lactoferrin is widely distributed in mammalian milk and other tissues and their secretions (including internal and external secretions such as tear fluid, bile, synovial fluid, and neutrophils). The concentration of lactoferrin in human milk is approximately 1.0-3.2mg/ml, which is 10 times of cow's milk (the content of cow's milk is 0.02-0.35mg/ml), accounting for 20% of the total protein of ordinary breast milk. During lactation, the content of lactoferrin varies with the time of lactation. Changes occur, for example, the lactoferrin in human colostrum can reach 6-14mg/ml, and it drops to 1mg/ml during normal lactation.

Lactoferrin and its protein degradation product-lactoferrin peptide has a wide range of biological activities, including broad-spectrum antibacterial effects, anti-inflammatory, inhibiting tumor cell growth and regulating the body's immune response, etc. It is considered a new type of antibacterial and anticancer drug And food and cosmetic additives with great development potential, such as the US Food and Drug Administration has long allowed lactoferrin to be used as a food additive in sports and functional foods.

Biological functions of lactoferrin

In the past ten years, laboratories around the world have conducted extensive studies on the functions of lactoferrin, especially the biological functions. Many new functions are being discovered continuously. Functions such as immune regulation, anti-infection and inhibition of tumor growth.

The following aspects of biological function:

1. Participate in iron metabolism and promote iron absorption.

Lactoferrin can increase the bioavailability of iron in intestinal cells, stabilize iron ions in a reduced state, and reduce the stimulating effect of iron ions on the gastrointestinal tract. Lactoferrin can maintain the balance of iron in the body by regulating the absorption of iron by intestinal mucosal cells according to the body's demand for iron.

2. Anti-microbial function.

Among the many biological functions of lactoferrin, the antimicrobial activity is the most striking. Lactoferrin can inhibit and kill many microorganisms, including G+ and G-aerobes, anaerobes, and some fungi. effect.

3. Antiviral effect.

Lactoferrin is a member of the non-specific immune system and has distinctive antiviral activity. It mainly binds to the surface protein of the virus or host cell or both, and exerts an antiviral effect in the process of virus adsorption and invasion.

Fourth, immune regulation and anti-infection.

Studies have shown that lactoferrin is a component of the human innate non-specific immune system. On the surface of secretion and epithelial cells, it exerts antimicrobial effects by inhibiting microbial reproduction, adsorption or (and) killing microbes, and participates in the body's anti-inflammatory process.

5. Anti-tumor.

Although iron-saturated lactoferrin can promote normal cell proliferation, it prevents cancer cells instead of stimulating them.

6. Antioxidant effect.

Under normal circumstances, the intracellular antioxidant defense system maintains a dynamic equilibrium state for the generation and removal of free radicals, and will not cause damage to the body's tissues and cells.

7. As a cell growth factor.

With the study of the effect of lactoferrin on osteoblasts, it has been found that lactoferrin can not only promote the proliferation and differentiation of primitive osteoblasts at physiological concentrations, but also reduce the apoptosis of osteoblasts and inhibit osteoclasts. The role of cell proliferation promotes survival opportunities for osteoblasts.

8. Other physiological functions

1. Inhibit the accumulation of cholesterol and participate in lipid metabolism: Lactoferrin participates in body lipids by increasing high-density lipoprotein (HDL) and reducing low-density lipoprotein (LDL) concentration, reducing cholesterol and triacylglycerol in the liver and blood metabolism.

2.  Regulate gene transcription: after lactoferrin binds to some cell surface receptors, such as nucleolin, it enters the cell through endocytosis and is transmitted to the nucleus, and then binds to specific DNA and RNA sequences to regulate these genes The transcription process*.
   

3. Antithrombotic effect: Lactoferrin receptors are expressed on the platelet membrane, which can prevent platelet aggregation after adenosine diphosphate (ADP) treatment; lactoferrin can prevent fibrinogen from binding to ADP-activated platelets; lactoferrin It can prevent platelet aggregation, thrombosis, the release of serotonin and the expression of α-granule membrane protein.

4. Analgesic effect: Under natural conditions, exogenous lactoferrin is usually derived from mammalian milk, which is not easy to produce tolerance, and lactoferrin itself has a significant anti-injury effect. Therefore, it is suggested that lactoferrin may become A natural medicine for pain.

Function applicationAntiviral effect of lactoferrin

①Lactoferrin mainly acts in the early stage of infection or the stage of virus adhesion, and prevents the virus from infecting cells by interfering with the contact between the virus and the cell;

②Natural, complete and correctly folded lactoferrin has a better anti-virus effect;

③The antiviral effect of lactoferrin has nothing to do with its ability to bind iron and other metal ions;

④ Virus inhibition increases with the increase of lactoferrin concentration;

⑤Lactoferrin has broad-spectrum antiviral properties and has varying degrees of inhibitory effects on various viruses.