Human Proteins

8/12/2019 Human Proteins

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HUMAN PROTEINS

Notes in Bioinformatics


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Insulin

Model of six insulin molecules assembled in a hexamer, highlighting the

threefold symmetry, the zincion holding it together (pink sphere), and

the histidineresidues (pink sticks) involved in zinc binding. Inactive

insulin is stored in the body as a hexamer, while the active form is the

monomer

Insulin is a peptide hormone,

produced by beta cells in thepancreas, and is central to

regulating carbohydrate and

fat metabolism in the body. It

causes cells in the skeletal

muscles, and fat tissue to

absorb glucose from the

blood.
http://en.wikipedia.org/wiki/Symmetryhttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Histidinehttp://en.wikipedia.org/wiki/Histidinehttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Symmetry


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Insulin is a very old protein that may have originated more

than one billion years ago. The molecular origins of insulin go

at least as far back as the simplest unicellular eukaryotes.

Apart from animals, insulin-like proteins are also known to

exist in Fungi and Protista kingdoms.

Insulin stops the use of fat as an energy source by inhibiting

the release of glucagon. Except in the presence of themetabolic disorder diabetes mellitusand metabolic

syndrome, insulin is provided within the body in a constant

proportion to remove excess glucose from the blood, which

otherwise would be toxic. When blood glucose levels fallbelow a certain level, the body begins to use stored sugar as

an energy source through glycogenolysis, which breaks down

the glycogen stored in the liver and muscles into glucose,

which can then be utilized as an energy source.
http://en.wikipedia.org/wiki/Eukaryoteshttp://en.wikipedia.org/wiki/Glucagonhttp://en.wikipedia.org/wiki/Diabetes_mellitushttp://en.wikipedia.org/wiki/Metabolic_syndromehttp://en.wikipedia.org/wiki/Metabolic_syndromehttp://en.wikipedia.org/wiki/Glycogenolysishttp://en.wikipedia.org/wiki/Glycogenolysishttp://en.wikipedia.org/wiki/Metabolic_syndromehttp://en.wikipedia.org/wiki/Metabolic_syndromehttp://en.wikipedia.org/wiki/Diabetes_mellitushttp://en.wikipedia.org/wiki/Glucagonhttp://en.wikipedia.org/wiki/Eukaryotes


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Growth Hormone

Somatotropine

Growth hormone (GH or HGH),

also known as somatotropin or

somatropin, is a peptide hormone

that stimulates growth, cell

reproduction and regeneration in

humans and other animals. It is a

type of mitogen which is specificonly to certain kinds of cells.

Growth hormone is a 191-amino

acid, single-chain polypeptide that

is synthesized, stored, and secretedby somatotropic cells within the

lateral wings of the anterior

pituitary gland


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Androgen


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Androgen, or androgenic hormone or testoid, is the broad

term for any natural or synthetic compound, that stimulates

or controls the development and maintenance of malecharacteristics in vertebrates by binding to androgen

receptors. This includes the activity of the accessory male sex

organs and development of male secondary sex

characteristics. Androgens were first discovered in 1936.Androgens are also the original anabolic steroids and the

precursor of all estrogens. The primary and most well-known

androgen is testosterone.Dihydrotestosterone (DHT) and

androstenedione are less known generally, but are of equalimportance in male development. DHT in the embryo life

causes differentiation of penis, scrotum and prostate. Later in

life DHT contributes to male balding, prostate growth and

sebaceous gland activity.


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Estrogen

Oestrogens or estrogens are a group of

compounds named for their importance in

both menstrual and estrous reproductive

cycles. They are the primary female sex

hormones. Natural estrogens are steroid

hormones, while some synthetic ones are

non-steroidal.

Estrogens are synthesized in all

vertebrates[2] as well as some insects. Their

presence in both vertebrates and insectssuggests that estrogenic sex hormones have

an ancient evolutionary history.


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KeratinKeratin is a family of fibrous

structural proteins. Keratin is the key

structural material making up theouter layer of human skin. It is also

the key structural component of hair

and nails. Keratin monomers

assemble into bundles to formintermediate filaments, which are

tough and insoluble and form strong

unmineralized tissues found in

reptiles, birds, amphibians, and

mammals. The only other biological

matter known to approximate the

toughness of keratinized tissue ischitin

Hornssuch as those of the impalaare

made up of keratin covering a core oflive bone
http://en.wikipedia.org/wiki/Horn_(anatomy)http://en.wikipedia.org/wiki/Impalahttp://en.wikipedia.org/wiki/Impalahttp://en.wikipedia.org/wiki/Horn_(anatomy)


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the -keratins in the hair (including wool), horns, nails, claws

and hooves of mammals[verification needed]

the harder -keratins found in nails and in the scales and

claws of reptiles, their shells (Testudines, such as tortoise,turtle, terrapin), and in the feathers, beaks, claws of birds and

quills of porcupines.[9] (These keratins are formed primarily

in beta sheets. However, beta sheets are also found in -

keratins.)[10]

The baleen plates of filter-feeding whales are made of keratin.


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Chitin (C8H13O5N)n is a long-chain polymer of a N-

acetylglucosamine, a derivative of glucose, and is found in

many places throughout the natural world. It is the main

component of the cell walls of fungi, the exoskeletons of

arthropods such as crustaceans (e.g., crabs, lobsters andshrimps) and insects, the radulae of molluscs, and the beaks

and internal shells of cephalopods, including squid and

octopuses. The structure of chitin is comparable to the

polysaccharide cellulose, forming crystalline nanofibrils orwhiskers. In terms of function, it may be compared to the

protein keratin. Chitin has also proven useful for several

medical and industrial purposes.

Chitina Carbohydrate


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http://en.wikipedia.org/wiki/File:Collagentriplehelix.png


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Collagen

Collagen is the main structural protein of the various

connective tissues in animals. As the maincomponent of connective tissue, it is the most

abundant protein in mammals, making up from 25%

to 35% of the whole-body protein content. It is

usually found in the skin, muscle, tendons, cartilage,bones and nerve tissues.

Tropocollagen triple helix
http://en.wikipedia.org/wiki/File:Collagentriplehelix.pnghttp://en.wikipedia.org/wiki/File:Collagentriplehelix.pnghttp://en.wikipedia.org/wiki/File:Collagentriplehelix.pnghttp://en.wikipedia.org/wiki/File:Collagentriplehelix.png


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HaemoglobinHaemoglobin is the iron-containing

oxygen-transport metalloprotein in

the red blood cells of allvertebrates (with the exception of

the fish family Channichthyidae) as

well as the tissues of some

invertebrates. Hemoglobin in theblood carries oxygen from the

respiratory organs (lungs or gills) to

the rest of the body (i.e. the

tissues) where it releases the

oxygen to burn nutrients to

provide energy to power the

functions of the organism in the

process called metabolism.


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Melanin

Melanin is a broad term for a

group of natural pigments

found in most organisms

(arachnids are one of the few

groups in which it has not

been detected). Melanin isproduced by the oxidation of

the amino acid tyrosine,

followed by polymerization.

The pigment is produced in aspecialized group of cells

known as melanocytes.

Part of the structural formula of pheomelanin.

"(COOH)" can be COOH or H, or (more rarely)

other substituents. The arrows denote where

the polymer continues.
http://en.wikipedia.org/wiki/Substituenthttp://en.wikipedia.org/wiki/Substituent


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Albinism occurs when melanocytes

produce little or no melanin. This albino

girl is from Papua New Guinea.


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Elastin

Elastin is a protein in connective

tissue that is elastic and allows

many tissues in the body to

resume their shape after

stretching or contracting. Elastin

helps skin to return to its originalposition when it is poked or

pinched. Elastin is also an

important load-bearing tissue in

the bodies of vertebrates and usedin places where mechanical energy

is required to be stored. In

humans, elastin is encoded by the

ELN gene.


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ProgesteronProgesterone is an

endogenous steroid hormone

involved in the menstrual

cycle, pregnancy, and

embryogenesis of humans

and other species.Progesterone is also a crucial

metabolic intermediate in the

production other endogenous

steroids, including the sexhormones and the

corticosteroids, and plays an

important role in brain

function as a neurosteroid


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FerritinFerritin is a ubiquitous intracellular

protein that stores iron and releases it in

a controlled fashion. The protein isproduced by almost all living organisms,

including algae, bacteria, higher plants,

and animals. In humans, it acts as a

buffer against iron deficiency and ironoverload. Ferritin is found in most

tissues as a cytosolic protein, but small

amounts are secreted into the serum

where it functions as an iron carrier.

Plasma ferritin is also an indirect marker

of the total amount of iron stored in the

body, hence serum ferritin is used as a

diagnostic test for iron deficiency

anemia


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Pro-Thrombin

Prothrombin (coagulation

factor II) is proteolyticallycleaved to form thrombin in

the coagulation cascade,

which ultimately results in

the reduction of blood loss.

Thrombin in turn acts as a

serine protease that

converts soluble fibrinogen

into insoluble strands of

fibrin, as well as catalyzing

many other coagulation-

related reactions

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