Enzymes

Enzymes

This chapter is prepared for PharmD students in accordance with the officially endorsed curriculum in Pakistan.

August 29, 2023

Chapter outline
» Introduction
» Enzymes obtained from plant source (phytoenzymes)
› Papain, bromelain, and malt extract
» Enzymes obtained from animal source
› Pepsin, pancreatin, pancrelipase, and rennin
» Miscellaneous enzymes

Introduction
» Enzymes are organic catalysts produced by living organisms
» They make possible the many complex chemical reactions that make up life processes
» Although produced by living organisms, enzymes are lifeless
» When isolated, they still exert their characteristic catalytic effect
» Although their chemical composition varies, they do exhibit several common properties
› Enzymes are colloids and are soluble in water and dilute alcohol, but are precipitated by concentrated alcohol
› Most enzymes act best at temperatures between 35 °C and 40 °C
› Temperatures above 55 °C, especially in the presence of moisture usually completely destroy them
› Their activity is negligible at 0 °C
› Certain heavy metals, formaldehyde, and free iodine retard the enzyme’s activity
› Their activity is markedly affected by the pH of the medium in which they act or the presence of other substances in this medium
› They are usually highly selective in their action
» The enzymes are proteins that range in molecular weight from about 13,000 to as much as 840,000
» Enzymes often occur in combination with inorganic or organic substances that have an important part in the catalytic action
› If these are nonprotein organic compounds, they are known as coenzymes
› If they are inorganic ions, they are referred to as activators
» Coenzymes are integral components of a large number of enzyme systems
» Several vitamins (thiamine, riboflavin, and nicotinic acid) are recognized as having a coenzymatic function
» Because enzymes may be recovered from plant and animal cells and because many have been purified
› They are utilized as therapeutic agents
» Esterases: Enzymes that hydrolyze esters into acids and alcohols or phenols
› Examples: Lipase, phospholipase, acetylcholinesterase, etc.
» Carbohydrases: Enzymes that catalyze the carbohydrates into simple sugars
› Examples: Diastase, lactase, maltase, invertase, cellulase, hyaluronidase, glucuronidase, etc.
» Nucleases: Enzymes that cleave the chains of nucleotides in nucleic acids
› Examples: Ribonuclease, desoxyribonuclease, nucleophosphatase, etc.
» Amidases: Enzymes that catalyze the hydrolysis of amides
› Examples: Arginase, urease, etc.
» Proteolytic enzymes: Enzymes that break down protein
› Examples: Pepsin, trypsin, chymotrypsin, papain, fibrinolysin, streptokinase, urokinase, etc.

Enzymes obtained from plant sources (Phyto-enzymes)

Papain
» Papain is the dried and purified latex of the fruit of Carica papaya (پپیتا) (Family Caricaceae)
» Papain is also called ‘vegetable pepsin’ because it contains enzymes somewhat similar to pepsin
› However, unlike pepsin, papain acts in acid, neutral, or alkaline media

Fruit
» Papaya tree attains a height of about 5 or 6 meters
» The fruit grows to a length of about 30 cm and a weight of 5 kg
» The epicarp adheres to sarcocarp (Figure 1)
» Sarcocarp is orange colored and fleshy
» Sarcocarp surrounds the central cavity containing a mass of nearly black seeds

Preparation of papain
» The full grown but unripe fruit is subjected to shallow incisions on the four sides
» The latex flows freely for a few seconds, but soon coagulates
» After collection, the coagulated lumps are shredded and dried by the sun or by the use of artificial heat
› Artificial heat method produces a better grade of crude papain
» Incisions and collections are made at weekly intervals as long as the fruit exudes the latex
» The crude papain is purified by dissolving in water and precipitating with alcohol

Constituents of papain
» Papain contains several enzymes
» One or more proteolytic enzymes, among which is peptidase I, capable of converting proteins into dipeptides and polypeptides
» A rennin-like coagulating enzyme that acts on casein of milk
» An amylolytic enzyme (converting starch into sugar)
» A clotting enzyme similar to pectase (pectase breaks down pectin)
» An enzyme that has a feeble activity on fats
» It is quite apparent that more than one proteolytic enzymes are present
› Because a single sample of papain yields variable results, depending on the protein used

Standards
» Papain is capable of digesting about 35 times its own weight of lean meat
» The best grade of papain digests 300 times its own weight of egg albumin

Uses
» Digestant for proteins (like pepsin), used as a digestive aid
» Used to relieve the symptoms of episiotomy (episiotomy: vaginal incision to aid childbirth)
» Debridement
› Removal of dead tissue or components of tissues e.g., proteins and nucleic acids
› Usually after trauma or after surgery
» An ingredient in the cleaning solution for contact lenses
» In the meat packing industry, for tenderizing beef
» In leather industry, for tanning hides into leather
___

>>> What is tanning and how papain can be helpful in this process?
>>> Can papaya fruit help in cooking meat? If yes, how?

Figure 1: Papaya fruit

Figure 1: Papaya fruit

Bromelain
» Bromelains, bromelain, or bromelin is a mixture of protein digesting and milk clotting enzymes obtained from the juice of pineapple plant, Ananas comosus (Family Bromeliaceae)
» Bromelain also occurs in the stem of the plant
» It differs from papain because it is obtained from both the ripe and unripe fruits

Cultivation, collection, and preparation
» Pineapple is a perennial plant
» The fruits are left on the plant to ripen for the full flavor to develop
» Dark green unripe fruits gradually change to yellow and finally to deep orange
» The fruits are cut off
» The enzyme bromelin does not disappear as the fruit ripens
» Bromelain is isolated from pineapple juice by precipitation with acetone and also with ammonium sulfide

Chemical Constituents
» Bromelain is not a single substance, but rather a collection of enzymes and other compounds
» It is a mixture of sulphur-containing protein-digesting enzymes, called proteolytic enzymes or proteases
» It also contains several other substances in smaller quantities, including peroxidase, acid phosphatase, protease inhibitors, and calcium

Uses
» Adjunct therapy to reduce inflammation and edema
» To accelerate tissue repair, especially following episiotomy
» In the treatment of surgical trauma and debridement of wounds
» In the production of protein hydrolysates
» Tenderizing meats
» In leather industry, for tanning hides into leather
» Ananase®

Malt Extract
Barley or barley grain (جو)
» Barley is the dried grains of one or more varieties of Hordeum vulgare (Family Gramineae)
» Barley is grown throughout the world wherever the climate is favorable
» Barley is one of the oldest cultivated cereals
» It is an annual erect herb resembling wheat

Malt or malted barley
» Malt or malted barley is dried, artificially germinated barley grains
» To prepare malt, heaps of barley grains are kept wet with water in a warm room and allowed to germinate until the caulicle protrudes
› The grain is then quickly dried
› The enzyme diastase in the moist warm grains converts the starch to maltose, thereby stimulating the embryo to growth
› The embryo is killed when the grains are dried
» Dry malt resembles barley but is crisper, has an agreeable odor, and has a sweet taste
» Malt contains
› Maltose (50 to 70%)
› Dextrins (2 to 15)
› Proteins (8%)
› Diastase (an amylolytic enzyme)
› A peptase enzyme
» Malt is used extensively in the brewing and alcohol industries
› Malt contributes the sugars necessary for fermentation

Malt extract
» Malt extract is the product obtained by extracting malt, the partially and artificially germinated grains of one or more varieties of Hordeum vulgare (Family Gramineae)
» The malt is infused with water at 60 °C and the expressed liquid is concentrated at a temperature not exceeding 60 °C, preferably under reduced pressure
» Malt extract may be mixed with 10% by weight of glycerin
» Malt extract contains
› Dextrin
› Maltose
› A small amount of glucose
› Diastase (an amylolytic enzyme)
» Malt extract can convert not less than 5 times its weight of starch into water soluble sugars
» Many commercial extracts of malt do not contain diastase
› Diastase is destroyed by the heat used for their sterilization
› Such extracts should not be confused with the malt extract (discussed above)
› Such extracts are used as bulk-producing laxatives
› Maltsupex®
» Diastase is a yellowish white, amorphous powder obtained from an infusion of malt
› Diastase can convert 50 times its weight of potato starch into sugars

Uses and dose
» Malt extract and purified diastase, both are used as amylolytic enzymes and as an aid in digesting starch
» Malt extract is used as a bulk producing laxative
» Malt extract is used to enhance flavors in foods like breakfast cereals
___

>>> What is ‘infusion’?
>>> How does ‘infusion’ differ from ‘digestion’?
>>> What is the link between ‘barley’, ‘malt’, and ‘malt extract’?

Enzymes obtained from animal source

Pepsin
» Pepsin is a substance containing a proteolytic enzyme obtained from the glandular layer of the fresh stomach of the hog, Sus scrofa var. domesticus (Family Suidae)

Preparation of pepsin
» Pepsin is prepared by digesting the minced stomach linings with hydrochloric acid (HCl)
» This solution is clarified, partially evaporated, dialyzed, concentrated, and
› Either poured on glass plates to dry, thus forming ‘scale pepsin’, or
› Carefully evaporated in a vacuum, forming ‘spongy pepsin’

Properties of pepsin
» Pepsin occurs as lustrous, transparent, or translucent scales, as granular or spongy masses
» Ranges in color from light yellow to light brown, or as fine white or cream-colored amorphous powder
» It is free from offensive odor
» Has a slightly acid or saline taste

Standards
» Pepsin digests not less than 3000 and not more than 3500 times its weight of coagulated egg albumin
» A pepsin of higher digestive power may be reduced to the standard by admixture with a pepsin of lower power or with lactose
» Pepsin produced commercially, especially spongy pepsin, often is 4 to 5 times as active as that used medicinally

Uses
» Pepsin is administered to assist gastric digestion
» It is a proteolytic enzyme and should preferably be given after meals
» Usual dose is 500 mg
» It is often combined with pancreatin in product formulations

Pancreatin
» Pancreatin is a substance containing enzymes principally amylase, lipase, and protease
» It is obtained from the pancreas of the hog Sus scrofa var. domesticus (Family Suidae), or of the ox, Bos taurus (Family Bovidae)

Preparation of pancreatin
» The fresh glands are minced and extracted by methods similar to those employed in the manufacture of pepsin

Properties of pancreatin
» Pancreatin is a cream-colored amorphous powder
» Has a faint, characteristic, but not offensive odor
» Its greatest activity is in neutral or faintly alkaline solution
» More than traces of mineral acids or large amounts of alkali hydroxides render pancreatin inert
» An excess of alkali carbonates inhibits its action

Standards
» Pancreatin contains, in each mg, not less than 25 USP units of amylase activity, not less than 2 USP units of lipase activity, and not less than 25 USP units of protease activity
» Pancreatin of a higher digestive power may be labeled to indicate its strength in whole number multiples of the 3 minimum activities or may be diluted by appropriate admixture to conform to aforementioned specifications
» 1 USP unit of amylase activity is contained in the amount of pancreatin that digests 1 mg of dry USP Potato Starch Reference Standard
» 1 USP unit of lipase activity liberates 1 μEq of acid per minute at a pH of 9 and at 37° C
» 1 USP unit of protease activity digests 1 mg of casein, all under specified conditions

Uses
» Pancreatin is a digestive aid
» Used in the preparation of predigested foods for invalids
» Enteric coated granules of pancreatin have been used to treat infants with celiac disease and related pancreatic deficiencies
» Usual dose is 325 mg to 1 g, as tablets, capsules, or granules
» Panteric®

Pancrelipase
» Pancrelipase is essentially a more concentrated form of pancreatin
» It contains in each mg not less than 24 USP units of lipase activity, 100 USP units of amylase activity, and 100 USP units of protease activity
» Thus, the lipase activity is increased 12-fold, but the amylase and protease activity only 4-fold, when compared to pancreatin

Uses
» Employed as a digestive aid
» Pancrelipase increases the intestinal absorption of fat, thus aiding in the control of steatorrhea
» It is available in the form of capsules, powder packets, and tablets
» The usual dose range is 8,000 to 24,000 USP units of lipolytic activity prior to each meal or snack, to be determined by the practitioner according to the needs of the patient suffering from pancreatic insufficiency
» Pancrease®

Rennin
» Renin is the partially purified milk curdling enzyme obtained from the glandular layer of the stomach of the calf, Bos taurus (Family Bovidae)

Preparation of renin
» Minced glandular layer of the digestive stomach of the calf are macerated in 0.5% sodium chloride solution
» Filtered
» Filtrate is acidified with HCl and saturated with NaCl
» Renin is precipitated with NaCl, dried, and powdered

Properties of renin
» Renin occurs as a yellowish white powder, or as yellow grains or scales
» It has a characteristic and slightly saline taste
» Has a peculiar, not unpleasant odor

Standards
» Renin coagulates approximately 25,000 times its own weight of fresh cow’s milk

Uses
» Rennin can be used to coagulate milk, thus rendering it more digestible for convalescents (patients)
» It is also an ingredient in pepsin and rennin elixir
» Its principal use, however, is to coagulate milk for the manufacture of cheese
___

>>> What is cheese and how it is made?
>>> Is cheese Halal? Why do Muslims ask this question, especially in the Western World?
>>> What is whey?
>>> What is whey protein?
>>> Is whey protein Halal? Why do Muslims ask this question, especially in the Western World?
>>> What is the difference between ‘curd’ and ‘yogurt’?
>>> What is the difference between ‘rennin’ and ‘renin’?

Miscellaneous Enzymes
Trypsin
» Crystallized trypsin is a proteolytic enzyme crystallized from an extract of the pancreas gland of the ox, Bos taurus (Family Bovidae)
» It has been employed orally, topically, or by inhalation or local injection for debridement of necrotic and pyogenic surface lesions
» The current use of trypsin is primarily topical by aerosol application for wound and ulcer cleansing

Chymotrypsin
» Chymotrypsin is a proteolytic enzyme crystallized from an extract of the pancreas gland of the ox, Bos taurus (Family Bovidae)
» It is administered in solution to the posterior chamber of the eye, under the iris, to achieve zonal lysis

Hyaluronidase
» Hyaluronidase for injection is a sterile, dry, soluble, enzyme product prepared from mammalian testes
» Hyaluronidase is a mucolytic enzyme capable of depolymerizing and catalyzing hyaluronic acid and similar hexosamine containing polysaccharides
» It is also a spreading factor and a diffusing factor
» Because of its action on hyaluronic acid, this enzyme promotes diffusion and hastens the absorption of subcutaneous infusions

Streptokinase and Streptodornase
» Streptokinase and streptodornase are 2 enzymes discovered from hemolytic streptococci
» In combination, are applied locally or topically wherever clotted blood or fibrinous or purulent accumulations appear following injury to the tissues
» Streptokinase breaks down fibrin, whereas streptodornase affects deoxyribonucleic acid and desoxyribonucleoprotein, which are the chief constituents of pus and necrotic tissue
» The enzyme combination is available as an injection for intramuscular use, as a solution or jelly for topical application, and as tablets for buccal and oral administration
» Indicated for massive pulmonary emboli and for extensive thrombi of the deep veins in adults
» Streptase®

Urokinase
» Urokinase is isolated from human urine
» This enzyme has thrombolytic activity and is used as an alternative to streptokinase in the treatment of massive pulmonary emboli
» Urokinase has a reduced probability of serious allergic reactions, because it is of human origin
» Abbokinase®

Sutilains
» Sutilains is a substance containing proteolytic enzymes derived from the bacterium Bacillus subtilis
» Applied topically, in an ointment form, 2 to 4 times daily, for wound debridement

Commonly available brands in Pakistan
» Dilcozyme® [CCL Pharmaceuticals]
› Ingredients: Cyanocobalamin, Folic Acid, Nicotinamide, Papain, Pepsin, Pyridoxine, Riboflavin, Thiamine

» Camozyme® [Chas. A. Mendoza]
› Ingredients: Nicotinamide, Papain, Pepsin, Pyridoxine, Riboflavin, Thiamine

» Pepzyme® [Shaigan Pharmaceuticals (Pvt) Ltd.]
› Ingredients: Bromelain, Metoclopramide, Pancreatin, Simethicone

» Plasenzyme® [Pacific Pharmaceuticals Ltd.]
› Ingredients: Bromelain, Metoclopramide, Pancreatin, Simethicone

» Phlogenzym® [Pacific Pharmaceuticals Ltd.]
› Ingredients: Bromelain, Rutin, Trypsin

» Eplazyme® [Epla Laboratories (Pvt) Ltd.]
› Ingredients: Amylase, Cyanocobalamin, Folic Acid, Nicotinamide, Papain, Pepsin, Pyridoxine, Riboflavin, Thiamine

» Kontab® [Efroze Chemical Industries (Pvt) Ltd.]
› Ingredients: Bromelain, Trypsin

Reading References
» Tyler VE, Brady LR, Robbers JE. Pharmacognosy. Lea & Febiger, 7th edition, 1976.
» Tyler VE, Brady LR, Robbers JE. Pharmacognosy. Lea & Febiger, 9th edition, 2003.
» www.druginfosys.com.
» www.medicalnewstoday.com/articles/275517 [Accessed: August 27, 2023].

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