维生素与辅酶 vitamin and cofactors of enzyme. contents introduction water-soluble vitamins...

维生素与辅酶

Vitamin And Cofactors of Enzyme

contents

introduction

Water-soluble Vitamins

Lipid-soluble Vitamins

1 Introduction

Vitamins are essential nutrients that are required in the diet, usually in trace amounts, because they cannot be synthesized by the organism itself.

Necessary for maintenance of growth, health, metabolic homeostasis.

Dietary deficiency cause diseases—— ‘-penia’ s

1.1 Discovery of vitamins1.1 Discovery of vitamins ：：

Sun Simiao(Sun Simiao( 孙思邈孙思邈 )) Tang dynasty, Tang dynasty, Liver is applied to Liver is applied to night-blindness( nyctalopia)night-blindness( nyctalopia) Silverskin for Silverskin for

beriberi(beriberi( 脚气病） 脚气病） 1897 Dutch 1897 Dutch Dr. C. EijkmanDr. C. Eijkman Rice bran for beriberi Rice bran for beriberi 1906 GB 1906 GB F. G. HopkinsF. G. Hopkins Rats cannot survive on purified feed( including pr, fat, Rats cannot survive on purified feed( including pr, fat, sachsach

arides, minerals) arides, minerals) Normal growth with trace milk Normal growth with trace milk Nutritional co-factors—— VitaminNutritional co-factors—— Vitamin 。 。 without common chemical structure (aliphatic, aromatic, stewithout common chemical structure (aliphatic, aromatic, ste

roids and heterocyclic compound)roids and heterocyclic compound)

1.2 Classification of Vitamin1.2 Classification of Vitamin

Fat-soluble vitamins: A, D, E, and K Water-soluble vitamins: B complex vitamins, Folic acid and asc

orbic acid, also known as vitamin C.

Participate in modulation of certain functionsParticipate in modulation of certain functions Vitamin AVitamin A Antixerophthalmic ~ Antixerophthalmic ~ 抗干眼病抗干眼病 ~~Vitamin DVitamin D Antirachitic ~ Antirachitic ~ 抗佝偻病抗佝偻病 ~~Vitamin EVitamin E Antisterility ~ Antisterility ~ 抗不育抗不育Vitamin KVitamin K Antihaemorrhagic ~Antihaemorrhagic ~ 抗出血抗出血 ~~

Fat-soluble vitaminsFat-soluble vitamins

Co-enzymes that participate in group transfer

Vitamin B1 Antineuritic ~ 抗神经炎 ~Vitamin B2 Antistomatoglossic ~ 抗口舌炎 ~Vitamin B6 Pyridoxal ~ 抗皮肤炎 ~Vitamin B12 Anti-pernicious anaemia ~ 抗恶性贫血 ~Vitamin PP （ B5 ） Anti-pellagra ~ 抗癞皮病 ~Pantothenic acid(B3) Anti-keratic ~ 抗皮肤角膜炎 ~Biotin （ B7 ）生物素 Anti-seborrhea ~ 抗皮脂溢出 ~Folic acid 叶酸 Vitamin C

Anti-anemia ~ 抗贫血 ~ antiscorbutic ~ 抗坏血病 ~

Water-soluble Vitamins

2 Fat-soluble Vitamins2 Fat-soluble Vitamins

2.1 Vitamin A——retinols

VA2 dehydroretinol VA1 retinol

Retinol →retinal →retinoic acid

4 identified types: D2, D3, D4, D5 Most important of which are:

D2( 麦角钙化醇 ergocalciferol) D3( 胆钙化醇 cholecaciferol)

Functions:Functions: To promotes Ca, P intake and osteogenesis Active type: 11 ，， 25-dihydnxycholecalciferol 25-dihydnxycholecalciferol

2.2 Vitamin D (anti- osteomalacia ~)

RRVD2 VD2

VD3 VD3

VD4 VD4

VD5VD5

Active form

vitamin D–binding protein (Dvitamin D–binding protein (DBP), also known as transcalcifBP), also known as transcalciferinerin

1 ， 25- 二羟胆钙化醇

Participate in modulation of Ca-P balance (absorption, mobilization, osteogenesis and renal reuptake)

Elevate blood phosphorus and calcium concentration

Promote osteogenesis/ calcification

The functions ofThe functions of 11 ，， 25-dihydnxycholecalciferol25-dihydnxycholecalciferol

Centchroman derivate Centchroman derivate

Nature structure: Nature structure:

tocopherol & tocopherol & 生育三烯酚 生育三烯酚 Each type is divided, according to methyl numbEach type is divided, according to methyl numb

er and position, into 8 kinds,er and position, into 8 kinds,αα, , ββ, , γγ, , δδ, etc. , etc.

αα – tocopherol – tocopherol has the strongest activity has the strongest activity

2.3 Vitamin E ( tocopherol)2.3 Vitamin E ( tocopherol)

母育酚（ tocol ）

α- 生育酚（ α-tocopherol ， 5,7,8-trimethyltocol ） β- 生育酚（ β-tocopherol ， 5,8-dimethyltocol ） γ- 生育酚（ γ-tocopherol ， 7,8-dimethyltocol ） δ- 生育酚（ δ-tocopherol ， 8-methyltocol ） ζ2- 生育酚（ ζ2-tocopherol ， 5,7-dimethyltocol ） η- 生育酚（ η- tocopherol ， 7-methyltocol ） ε- 生育酚（ ε-tocopherol ） ζ1- 生育酚（ ζ1-tocopherol ）

structure

(1) Antioxidation (1) Antioxidation ，， protect unsaturated fatty acids in protect unsaturated fatty acids in

membranes . When human plasma levels are low, red bmembranes . When human plasma levels are low, red b

lood cells are increasingly subject to oxidative hemolysilood cells are increasingly subject to oxidative hemolysi

s. s.

(2) Maintain procreative function. Deficiency causes a(2) Maintain procreative function. Deficiency causes a

mbloma.mbloma.

Functions:Functions:

Plant oil Beans vegetables

Sourses:

Naphthoquinone with isoprene sidechain Naphthoquinone with isoprene sidechain

K1, K2, K3. K3 is synthetic. K1, K2, K3. K3 is synthetic.

K1K1 、、 K2 are 2-ethyl -1,4- napthalene derived K2 are 2-ethyl -1,4- napthalene derived

2.4 Vitamin K2.4 Vitamin K

To promote blood coagulation; To promote blood coagulation;

Important factors in hepatic synthesis of thromImportant factors in hepatic synthesis of throm

binogen and other blood coagulation factors .binogen and other blood coagulation factors .

Functions:Functions:

Carboxylation of Glu into Carboxylation of Glu into γ-thrombinogen depends on thrombinogen depends on enzymes with Vkenzymes with Vk

fibrae sanguisfibrae sanguis

thrombinthrombin

Unsoluble fibrin clotUnsoluble fibrin clot

thromboplastic proteinthromboplastic protein

Phospholipid, CaPhospholipid, Ca2+2+

thrombinogenthrombinogenVitamin KVitamin K

Plasma thrombinPlasma thrombin

Vitamin KVitamin K33

Structure:Structure:

Food: Food: Vegetables, animal liver, fish Vegetables, animal liver, fish

Milk, beans Milk, beans Intestinal microorganisms Intestinal microorganisms

Source:Source:

3. Water-soluble vitamins3. Water-soluble vitamins and cofactors of enzyme and cofactors of enzyme

Constitute of an amino pyrimidine ring and a sul

fur-containing thiazole ring

Active form in vivo:

焦磷酸硫胺素 TPP( thiamine pyrophosphate)

3.1 Vitamin B1

*

*

pyrimidine ring thiazole ring

Structure

(1) Coenzyme for (1) Coenzyme for decarboxylasesdecarboxylases

Functions

(2) Coenzyme for (2) Coenzyme for transketolasestransketolases

Properites: easy soluble in water, acidic. stable in acidic solution

vulnerable to neutral and alkalic condition Sources:

Plant: cereals, beans Yeast

Unit∶ 1IU≈3μg pure VB1 hydrochloride

Vitamin B2 is also named as Vitamin B2 is also named as Riboflavin Riboflavin Green fluorescent in solutionGreen fluorescent in solution Part of prosthetic groups of oxidoreductasePart of prosthetic groups of oxidoreductase

3.2 Vitamin B2 and FMN, FAD3.2 Vitamin B2 and FMN, FAD

Structure

FMNFMN∶∶ Flavin mononucleotide Flavin mononucleotide 黄素单核黄素单核苷酸 苷酸

FADFAD∶∶Flavin Adenine DinucleotideFlavin Adenine Dinucleotide 黄素黄素腺嘌呤二核苷酸腺嘌呤二核苷酸

FMN, FAD——prosthetic groups——tigFMN, FAD——prosthetic groups——tightly bind to enzyme htly bind to enzyme

Yellow Yellow →→flavoproteinflavoprotein

Strong oxidant that is reduced by 1 or 2 atoms: H transfer

FunctionsFunctions ： ： Promote saccharide, lipid and protein metabolism as prosynthePromote saccharide, lipid and protein metabolism as prosynthe

tic group. tic group. Protect mucosa, maintain visual function, promote growth.Protect mucosa, maintain visual function, promote growth.

DeficiencyDeficiency: : Weak respiratory system, low metabolism rate Weak respiratory system, low metabolism rate angular cheilitis(angular cheilitis( 口角炎口角炎 ), glossitis(), glossitis( 舌炎舌炎 ), conjunctivitis(), conjunctivitis( 结膜结膜

炎炎 ). ). Min intake for adults: Min intake for adults: 1.6mg/d 1.6mg/d No intoxication when overdosed.No intoxication when overdosed. Sources: Sources:

Wide existence in plants Wide existence in plants Rice bran, yeast, liver, yolk, etc..Rice bran, yeast, liver, yolk, etc..

Acidic compound of Acidic compound of αα, , γγ-dihydroxyl--dihydroxyl-ββ, , ββ-dimethylbutyric acid-dimethylbutyric acid

ββ-alanine -alanine phosphonic acid phosphonic acid

pantothenic acidpantothenic acid ββ-cysteamine -cysteamine

↓ ↓ 44´́-phosphopantetheine (4-phosphopantetheine (4´́-P-PaSH) -P-PaSH) + 5+ 5´́-adenylate-3-adenylate-3´́- phosphonic acid - phosphonic acid

↓ ↓ CoA-SH (CoA-SH ( 辅酶辅酶 AA ））

Su

lfatidate b

on

d facili

Su

lfatidate b

on

d facili

ates hyd

rolizatio

nates h

ydro

lization

3.3 Pantothenic acid (Vit. B3)3.3 Pantothenic acid (Vit. B3) & CoA-SH& CoA-SH

Participate in saccharide, lipid and protein metaboliParticipate in saccharide, lipid and protein metabolism in the form of sm in the form of CoA-SHCoA-SH Participate in fatty acid metabolism as prosynthetic group Participate in fatty acid metabolism as prosynthetic group

of acyl carrier protein of acyl carrier protein Acyl carrier of acylation and oxydation decarboxylationAcyl carrier of acylation and oxydation decarboxylation

（（ acyl- CoAacyl- CoA ：： saccharide and lipid oxidation. saccharide and lipid oxidation. Synthesis of acetylcholine, cholesterol, glycogen, modulates Synthesis of acetylcholine, cholesterol, glycogen, modulates

blood lipid. blood lipid. Effective to anorexia and debilitation Effective to anorexia and debilitation Ancillary drug for hepatitis and coronary heart diseAncillary drug for hepatitis and coronary heart dise

ase ase

Functions:Functions:

Wide existence. Wide existence. Liver, kidney, wheat, rice Liver, kidney, wheat, rice bran, yeast peanut.bran, yeast peanut.

Sources:Sources:

pellagra preventive factor or VPP pellagra preventive factor or VPP

Nicotinic Acid(Nicotinic Acid( 烟酸烟酸 ) & ) & Nicotinamide(( 烟酰胺烟酰胺 ))

4. Nicotinic Acid and CoⅠ,CoⅡ4. Nicotinic Acid and CoⅠ,CoⅡ

Oxidized form Reduced formOxidized form Reduced form NADNAD+ + NADH NADH

energy yielding catabolism energy yielding catabolism oxidized by respiratory chain oxidized by respiratory chain

NADPNADP++ NADPH NADPH reductions in assimilation reductions in assimilation

structure:structure:

Functions: Functions: Participate in metabolism as Participate in metabolism as coenzyme of anaerobic dehycoenzyme of anaerobic dehy

drogenasedrogenase H transfer H transfer Maintain health of neural system. Maintain health of neural system. Promote growth of microorganismsPromote growth of microorganisms

Deficiency: Deficiency:

Pellagra , diarrhea, dementiaPellagra , diarrhea, dementia Sources: Sources:

Synthesized from Ser. Synthesized from Ser. Yeast, liver, lean meat, milk, peanut, soybeanYeast, liver, lean meat, milk, peanut, soybean

吡哆醛吡哆醛 pyridoxal pyridoxal 吡哆胺吡哆胺 pyridoxamine pyridoxamine 吡哆醇吡哆醇 pyridoxine pyridoxine

3.5 VB6

磷酸吡哆醛 磷酸吡哆胺

structure:structure:

(1) Transamination

Functions

(2) Decarboxylation

(3) Coenzyme of (3) Coenzyme of serine transhydroxymethylaseserine transhydroxymethylase for one-ca for one-carbon unit transferrbon unit transfer

Thiophene + urea Thiophene + urea αα-biotin-biotin （（ yolkyolk ） ）

————isopentoic acid side chain isopentoic acid side chain ββ-biotin-biotin （（ liverliver ） ）

————pentanoic acid side chain pentanoic acid side chain

similar chemical and physiological characters similar chemical and physiological characters Wide existenceWide existence in in both animals and plants.both animals and plants.

3.6 Biotin (Vit. B7)3.6 Biotin (Vit. B7)

Co-enzyme/ prosynthetic group of carboxylase——CO2 fixation Co-enzyme/ prosynthetic group of carboxylase——CO2 fixation e.g. pyruvate carboxylase e.g. pyruvate carboxylase

pterolyglutamic acid(PGA)

3.7 Folic acid (Vit. B11)& CoF

（ 1 ） tetrahydrofolate (C

oF 、 FH4 、 THFA): Coenzyme of singel-carb

on metablism

Functions

(2) FH4 participate in pyrimidine synthesis promote protein composition

Deficiency : anaemia Sources: Green vegetables. Intestinal microorganisms