Biochemistry Vitamins, Nucleic Acids, Enzymes, and Hormones Overview

B1

• Thiamine

• Active form: TPP; Deficiency: beriberi; Krebs cycle/ electron transport

B2

• Riboflavin

• Active form: FAD, FADH2; Deficiency: ariboflavinosis; Krebs cycle/ electron transport

B3

• Niacin

• Active form: NAD, NADP; Deficiency: pellagra; Krebs cycle/ electron transport

B5

• Pantothenic acid 

• Active form: Coenzyme A

B6

• Pyridoxine 

• Requires zinc; Functions in amino acid metabolism

B9

• Folic acid 

• Methyl transfer; Needed in pregnancy for neural tube development

B12

• cobalamin

• Homocysteine methionine(methyl transfer): prevents CAD

• Functions in transamination and deamination reactions

B7

• Biotin

• Biotin binds to avidin; Acyl transfer reactions

Vitamin A

• Retinol/al, carotenoid

• Stored in liver; Deficiency: night blindness

Vitamin D

• Calciferol

• Stored in blood; 7-dehydrocholsterol is secreted to surface → ring b opens + rearranges → forms D3 → diffuses into blood

• Deficiency: autoimmune disfunction, dec bone mineral density

Vitamin E

• tocopherol(saturated), tocotrienol(unsaturated)

• Stored in adipose tissue; Antioxidant; Provides H for ROS

Vitamin K

• phyloquinone

• Stored in cell membrane, kidney, lungs, bone marrow;

• Functions in blood clotting; Deficiency: bleeding disorder

DNA structure

Backbone- sugar phosphate with phosphoester bond; Configuration- antiparallel dimer; Sugars- deoxyribose

Chromatin

DNA around a protein core; Histone Proteins- H2A, H2B, H3, H4 → H1 is the linker; 46 total chromosomes; 22 autosomal pairs; 1 pair of sex chromosomes

Purines

2 rings—Adenine and guanine

Pyrimidines

1 ring - Thymine, cytosine, uracil

Adenine (adenosine)

• Energy

• AMP,ADP,ATP,cAMP

Guanine (guanosine)

• TCA

• GMP, GDP,GTP,cGMP

Uracil (uridine)

• Glycogenolysis

• UMP,UDP,UTP

Cytosine (cytosine)

• Protein glycosylation

• CMP,CDP,CTP

Thymine (Thymidine)

• Protein synthesis

• TMP,TDP,TTP

Transcription

Occurs in the nucleus; Initiation- RNA polymerase binds to the promoter region; Elongation- base pairs added 5' to 3'; DNA reads 3' to 5'; Termination- stop codon, hairpin loop created

Translation

Occurs in the cytoplasm; Initiation- mRNA binds at start codon AUG/Met; Elongation- enters at A-site and peptide bond is formed; Termination- stop codon reached- protein is released

Hydrolases

Hydrolysis, cleaves by using a water molecule

Isomerase

Isomerases: Converts the monosaccharide aldose to ketose; Converts glucose to fructose in RBC

Ligases

Carboxylase: Function in the mitochondria—Krebs Cycle

Lyases

Anhydrase: Creation of bicarbonate from CO2 + H2O; Enzyme: carbonic anhydrase

Oxidoreductase

Decarboxylase: Requires thiamine (B1) and NAD; Enzyme: pyruvate dehydrogenase

Transferases

Transaminases: Transfers amino group in the muscle

Serum Glutamate Pyruvate Transaminase (SGPT)

Enzyme that transfers amino groups in the muscle.

Ribozymes

Catalytic RNA molecules that are not proteins.

Digestive Enzymes

Enzymes that aid in the breakdown of food.

Pancreatic Lipase

Enzyme that digests fats in the small intestine.

Pepsin

Enzyme produced by chief cells in the stomach that digests proteins.

HCl

Hydrochloric acid produced by parietal cells in the stomach.

Competitive Inhibitors

Inhibitors that bind to the active site of enzymes.

Non-Competitive Inhibitors

Inhibitors that bind to allosteric sites of enzymes.

Irreversible Inhibitors

Inhibitors such as heavy metals and nerve gas that permanently deactivate enzymes.

Amino Acids

Building blocks of proteins that have various functions.

Methionine

A sulfur-containing amino acid that is an antioxidant and involved in detoxification.

Cysteine

A sulfur-containing amino acid that requires B12 for its metabolism.

Alanine

An amino acid that requires SGPT to transaminase pyruvate to alanine.

Arginine

An amino acid involved in the detoxification of ammonia in the liver.

Aspartic Acid

An amino acid that is a precursor to both purines and pyrimidines.

Glutamic Acid

An amino acid that serves as a precursor to both purines and pyrimidines and detoxifies ammonia.

BCAA

Branched-chain amino acids that include leucine, valine, and isoleucine.

Phenylalanine

An amino acid that converts to tyrosine; defects can cause PKU.

Insulin

Hormone produced by pancreatic beta cells that decreases high blood sugar levels.

Glucagon

Hormone produced by pancreatic alpha cells that increases glucose levels in the blood.

Growth Hormone

Hormone released in response to sleep that stimulates the liver to make IGF-1.

Calcitonin

Hormone made in the thyroid gland that decreases blood calcium levels.

Hypoxanthine

• Inosine

• IMP

• formed from the breakdown of purines