FNN 100 Lecture 5: protein

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taupefish917

27 Nov 2017

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Fnn protein protein is long chains of amino acids. N enters food chain through n- xing bacteria in roots. 20aa"s indispensable, dispensable, conditionally indispensible essential aa"s used to make indispensable aa"s and other n compounds contain:amino group, carboxyl group, and h atom, and c side chain side chain noted as r . Histidine despensable (non-essential) aa"s can be synthesized in the body through transamination. Conditionally indespensable aa"s not synthesized at a rate to meet the body"s needs. Protein structure the structure determines function dipeptide: 2 aa residues tripeptide: 3 aa residues ogliopeptide: 4-9 peptide residues. Condensation of 2 aa"s to form a dipeptide acid group+ amine group form peptide bond and create a dipeptide. Protein structure primary linear sequence of aa secondary. Quaternary bond between subunits that comprise a functional protein. Why do proteins fold? so they can carry out their function.

Related Questions

Using the information in the table below, enter the correct pH that should be used to separate the following three amino acids by electrophoresis:

(a) Glu, Lys, and Thr: pH=?

(b) His, Lys, and Arg: pH=?

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pK_a Values for Ionizable Groups of Amino Acids.
Amino Acid	pK_a of Î±-COOH	pK_a of Î±-NH₃⁺	pK_a of Side Chain	Isoelectric Point (pI)
Alanine	2.35	9.87	-	6.11
Arginine	2.01	9.04	12.48	10.76
Asparagine	2.02	8.80	-	5.41
Aspartic acid	2.10	9.82	3.86	2.98
Cysteine	2.05	10.25	8.00	5.02
Glutamic acid	2.10	9.47	4.07	3.08
Glutamine	2.17	9.13	-	5.65
Glycine	2.35	9.78	-	6.06
Histidine	1.77	9.18	6.10	7.64
Isoleucine	2.32	9.76	-	6.04
Leucine	2.33	9.74	-	6.04
Lysine	2.18	8.95	10.53	9.74
Methionine	2.28	9.21	-	5.74
Phenylalanine	2.58	9.24	-	5.91
Proline	2.00	10.60	-	6.30
Serine	2.21	9.15	-	5.68
Threonine	2.09	9.10	-	5.60
Tryptophan	2.38	9.39	-	5.88
Tyrosine	2.20	9.11	10.07	5.63
Valine	2.29	9.72	-	6.00

The peptide hormone vasopressin is used in the regulation of Na+ in many vertebrate. Porcine(pig) vasopressin has the sequence Asp-Tyr-Phe-Glu-Asn-Cys-Pro-Lys-Gly.

a) What is the pI of this peptide? Use the pKa values in the table on the last page for your calculations.

b) Could this peptide have an a helical secondary structure? Why or why not.

c) Will this peptide absorb UV light(280nm)? Why?

Consider the peptide:
NH₂-GAPAGPAGTGKTETTKDLAKSMALLCWFNCS-COOH

Table I. pK values of some amino acids

amino acid	pK of side chain or terminal group
Alanine (Ala or A)	uncharged
Arginine (Arg or R)	12.5
Asparagine (Asn or N)	uncharged
Aspartic acid (Asp or D)	3.9
Cysteine (Cys or C)	8.3
Glutamic acid (Glu or E)	4.3
Glycine (Gly or G)	uncharged
Histidine (His or H)	6.0
Leucine (Leu or L)	uncharged
Lysine (Lys or K)	10.8
Phenylalanine (Phe or F)	uncharged
Serine (Ser or S)	uncharged
Tryptophan (Trp or W)	uncharged
Tyrosine (Tyr or Y)	10.9
Valine (Val or V)	uncharged
peptide N terminus	7.8
peptide C terminus	3.6

Using Table I above, determine the net charge of the peptide at pH9.

(the answer is not -1 or 1)

FNN 100 Lecture 5: protein

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