MRC-Holland’s Newly Developed SALSA HhaI Enzyme; News on Promega’s HhaI Enzyme
MRC-Holland has launched its own restriction enzyme SALSA HhaI (item number SMR51). A free vial will be included with all orders containing an MS-MLPA probemix from 3 April until 30 September 2018. There has also been some important information regarding the HhaI restriction enzyme supplied by Promega. This newsletter is intended to inform MS-MLPA users.

News on Promega’s HhaI enzyme
Recently, Promega sent their customers a letter stating that the enzymatic activity of certain lots of the HhaI enzyme was lower than indicated on the label. Promega has informed us that (contrary to earlier communication) they will continue selling the HhaI enzyme, and that they can still provide HhaI lots with the stated enzymatic activity.

MRC-Holland’s SALSA HhaI enzyme
For MS-MLPA users, MRC-Holland has made efforts to offer an alternative to ensure all our customers can continue using our MS-MLPA products satisfactorily.

For some time, MRC-Holland has been developing its own supply of the HhaI enzyme, as part of our objective to ensure that every aspect of (MS-)MLPA, from start to result interpretation, is of the highest standards. MRC-Holland would like to offer this HhaI enzyme free of charge to MS-MLPA users. The product description can be found here.

Some important information about our SALSA HhaI enzyme:
  • The enzyme is supplied for Research Use Only (RUO), as are all our MS-MLPA products.
  • The enzyme will be included free of charge with all orders containing an MS-MLPA probemix from 3 April until 30 September 2018.
  • Item number: SMR51 SALSA HhaI 1 vial for 100 MS-MLPA reactions.
  • Additional vials of HhaI enzyme can be ordered by including this article code on the order (within reasonable limits).
  • From November 2018 onward, the SALSA HhaI enzyme will be available separately at a reasonable cost.

We would like to remind you that certain enzymes, which are commercially provided as HhaI, are unsuitable for MS-MLPA as they cannot be completely heat inactivated. This includes, but may not be limited to, Thermo Fisher Scientific enzymes HhaI, ANZA 59 HhaI, and FastDigest HhaI.

Possible effects of using the affected Promega lots of HhaI enzyme with reduced enzymatic activity for MS-MLPA
MS-MLPA users may wonder what consequences the use of Promega HhaI enzyme with a reduced activity may have (had) for their MS-MLPA experiments. Fortunately, most MS-MLPA probemixes include so-called digestion control probes. In case of sufficient enzymatic activity, these probes will be completely digested by the HhaI enzyme. Coffalyser.Net issues a warning when the digestion of these probes is not complete, and the digestion of these probes can also be examined visually.

A limited number of MS-MLPA probemixes for use on tumour-derived DNA do not contain designated digestion control probes (ME001, ME002, ME011, ME043). These mixes however include probes for various genes, which, in blood-derived samples, should be fully digested. For these products, completeness of digestion is indicated by almost complete digestion of at least some of the methylation-sensitive probes.

If you have verified that digestion was successful, there is no need to be concerned about the reported reduction in HhaI enzyme activity.

In case you have any additional questions, please contact us at or via our support portal.
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