지방의 소화, 흡수, 분류 등 지질의 모든 것!! 정리중

[문형철]

Beyond reason

미량원소 치유의학의 세계

어떤 사람에게는 좋은 음식이 어떤 사람에게는 독이 될 수 있다

4장- 지질의 이해-1.pdf

지방의 소화, 흡수 그리고 기능은 생각보다 복잡하고 어렵다.

지방은 위액의 gastric lipase, 췌장액의 pancreatic lipase에 의해 모노글리세라이드+지방산으로 분해되어 소장에서 흡수됨. 담즙의 유화과정을 거쳐..

지방질 

- 에테르, 벤젠, 아세톤과 같은 지용성 유기용매에 잘 녹는 탄화수소계 화합물

- 1g당 9kcal 열량생산

지질의 분류

포화지방산과 불포화지방산의 정의

- 지방산이란 비극성탄화수소 한쪽끝에 카르복실기를 갖는 화합물

- 탄소이온이 4개의 단일결합을 하면 포화, 그렇지 못하면 불포화된 상태

지방산의 종류

1) 포화지방산 - 카프릴산, 라우린산, 미리스틴산, 팔미틴산, 스테아린산

   불포화지방산 - 오메가 3(리놀렌산, EPA, DHA)

                       오메가 6(리놀레산, 아라키돈산, )

                       오메가 9(콜레산, 올레인산)

                       리그난 

시스지방과 트랜스지방 이야기

트랜스지방은 대부분 포화지방산...

경화유

- 마가린과 버터이야기

중성지방(triglyceride)

A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from tri- and glyceride).^[1] Triglycerides are the main constituents of body fat in humans and other vertebrates, as well as vegetable fat.^[2] They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, and are a major component of human skin oils.^[3]

There are many different types of triglyceride, with the main division between saturated and unsaturated types. Saturated fats are "saturated" with hydrogen — all available places where hydrogen atoms could be bonded to carbon atoms are occupied. These have a higher melting point and are more likely to be solid at room temperature. Unsaturated fatshave double bonds between some of the carbon atoms, reducing the number of places where hydrogen atoms can bond to carbon atoms. These have a lower melting point and are more likely to be liquid at room temperature.

카일로마이크론

킬로미크론(chylomicron)은 창자 상피세포에서 합성되며 합성의 원료는 중성지방, 인지질, 콜레스테롤 등의 지질과 단백질이다. 킬로미크론은 창자 미세융모의 림프관을 타고 혈관(정맥)으로 이동한다. 이후 APOE(AOP단백질)와 결합하여 근육과 지방조직에 중성지방을 나눠주는 역할을 한다

Chylomicrons (from the Greek χυλός, chylos, meaning juice (of plants or animals), and micron, meaning small particle) are lipoprotein particles that consist of triglycerides (85–92%), phospholipids (6–12%), cholesterol (1–3%), and proteins (1–2%). Due to their density relative to lipoproteins, they are also commonly known as ultra low density lipoproteins (ULDL) in modern usage. ^[1] They transport dietary lipids from the intestines to other locations in the body. ULDLs are one of the five major groups of lipoproteins (sorted by density) that enable fats and cholesterol to move within the water-based solution of the bloodstream.^[2] A protein specific to chylomicrons is ApoB48.

There is an inverse relationship in the density and size of lipoprotein particles: the larger particles (higher ratio of fat molecules inside compared with the outer emulsifying protein molecules in the shell) and fats are always lower density than either protein or water molecules, i.e. fats float in water. ULDLs, being the least dense, are the largest and only lipoprotein particles that can sometimes (if large enough, at close to about 1,000 microns or more) be seen using only a light microscope, at maximum magnification. All the other classes are submicroscopic, one of the reasons these particles were long difficult to identify and better understand.

Function[edit]

Chylomicron structure
ApoA, ApoB, ApoC, ApoE (apolipoproteins); T (triacylglycerol); C (cholesterol); green (phospholipids)

Chylomicrons transport lipids absorbed from the intestine to adipose, cardiac, and skeletal muscle tissue, where their triglyceride components are hydrolyzed by the activity of the lipoprotein lipase, allowing the released free fatty acids to be absorbed by the tissues. When a large portion of the triacylglycerol core have been hydrolyzed, chylomicron remnants are formed and are taken up by the liver, thereby also transferring dietary fat to the liver.

Origin[edit]

Chylomicrons are formed in the endoplasmic reticulum in the absorptive cells (enterocytes) of the small intestine. The villi, lined with the microvilli of the brush border, provide a lot of surface area for absorption. Newly formed chylomicrons are secreted through the basolateral membrane into the lacteals, where they join lymph to become chyle. The lymphatic vesselscarry the chyle to the venous return of the systemic circulation. From there the chylomicrons supply the tissue with fat absorbed from the diet.^[3] Thus, unlike the saccharides and amino acids that digestion liberates from the carbohydrates and proteins of the diet (respectively), the lipids from the diet bypass the hepatic portal system, meaning the liver does not get "first crack" at them.

Stages[edit]

There are three stages in the chylomicron's "lifecycle":

• Nascent chylomicron
• Mature chylomicron
• Chylomicron remnant

Nascent chylomicrons[edit]

Triglycerides are emulsified by bile and hydrolyzed by the enzyme lipase, resulting in a mixture of fatty acids and monoglycerides. These then pass from the intestinal lumen into the enterocyte, where they are re-esterified to form triglycerides. The triglycerides are then combined with phospholipids, cholesteryl esters, and apolipoprotein B-48 to form a nascent chylomicron. These are then released by exocytosis from the enterocytes into the lacteals, lymphatic vessels originating in the villi of the small intestine, and are then secreted into the bloodstream at the thoracic duct's connection with the left subclavian vein.

Nascent chylomicrons are composed primarily of triglycerides (85%) and contain some cholesterol and cholesteryl esters. The main apolipoprotein component is apolipoprotein B-48 (apo B-48).

Mature chylomicron[edit]

While circulating in blood, chylomicrons exchange components with high-density lipoproteins (HDL). The HDL donates apolipoprotein C-II (APOC2) and apolipoprotein E (APOE) to the nascent chylomicron and, thus, converts it to a mature chylomicron (often referred to simply as "chylomicron"). APOC2 is the coenzyme for lipoprotein lipase (LPL) activity.

Chylomicron remnant[edit]

Once triglyceride stores are distributed, the chylomicron returns APOC2 to the HDL (but keeps APOE), and, thus, becomes a chylomicron remnant, now only 30–50 nm. APOB48 and APOE are important to identify the chylomicron remnant in the liver for endocytosis and breakdown.

[문형철]

https://m.blog.naver.com/PostView.nhn?blogId=hyouncho2&logNo=60170417299&proxyReferer=https%3A%2F%2Fwww.google.co.kr%2F

이 글 꼭 정리해야///