Neutral protease

For more than a quarter of a century this enzyme has been helping those in schools to extract DNA from onions. Don’t be fooled by people who say that kiwi fruit provide a less smelly alternative: the gooey stuff you extract from them is mainly pectin.

PRACTICAL PROTOCOL

DNA ISOLATION

SOURCE

Neutrase^® is a bacterial protease produced by a selected strain of Bacillus amyloliquefaciens. It will break down proteins to peptides.

COMMERCIAL USES

Neutrase^® is used commercially to ‘upgrade’ proteins of animal and vegetable origin, such as softening wheat gluten. It can also be used to remove the ‘stickwater’ around fish roe.

EDUCATIONAL USES

DNA extraction
Neutrase^® can be used to degrade proteins when preparing crude extracts of DNA from plant and animal cells (see link to the protocol on the left).

Clarifying milk
Neutrase^® can also be used instead of trypsin in the well-known school practical where skimmed milk is clarified by addition of the enzyme (use 10 mL of 3% w/v dried skimmed milk powder and add 1 mL of 10% v/v Neutrase^® solution to it. If the reaction is too fast, simply reduce the amount of Neutrase^®).

If you wish to demonstrate the denaturation of an enzyme by heating, Neutrase^® is a good one to use, but you do need to heat it to 85 °C for about 2 minutes to see this.

See also: Practical Biology. Quantitative food test. Protein content of powdered milk.

ACTIVITY

As its name implies, Neutrase^® is a neutral protease with an optimum activity around pH 5.5–7.5 and 30–55 °C. It is a metallo- proteinase, requiring zinc ions for its activity. Consequently, it is stabilised by the presence of calcium ions and inhibited by EDTA. The stability of Neutrase^® at a particular temperature is influenced by the type and concentration of the proteins present.

STORAGE

If it is stored at 3–5 °C, Neutrase^® will retain its declared activity for at least a year. Do not freeze.

SAFETY

DANGER. May cause allergy or asthma symptoms or breathing difficulties if inhaled. See Safety Data Sheet for further advice.

SAFETY DATA SHEET

NEUTRASE 0.8 L

ORDERING

All of the prices on this page are in GBP and do not include Value Added Tax (VAT). This tax applies within the European Union only. Postage and handling must also be paid on orders from outside the United Kingdom. Details of how to order are given on the price list and on the Ordering web page.

Please note: We are unable to supply this product to addresses in the United States of America.

PLEASE NOTE: THE NCBE SUPPLIES THESE ENZYMES TO SCHOOLS AND COLLEGES FOR EDUCATIONAL USE ONLY. COMMERCIAL USERS OF ENZYMES OR THOSE WHO REQUIRE ENZYMES FOR RESEARCH PURPOSES SHOULD CONTACT THE ENZYME MANUFACTURERS OR OTHER SUPPLIERS, NOT THE NCBE.