WEB3.JS problem

I am trying to use the library “ethereumjs-tx” but it does not work.
I get this error message: “TypeError: Tx is not a constructor” on the code “const tx = new Tx(txObject)”.

Here is my code:

const Tx = require(‘ethereumjs-tx’)

const txObject = {

    nonce: web3.utils.toHex(txCount),

    to: account2,

    value: web3.utils.toHex(web3.utils.toWei('0.3', 'ether')),

    gasLimit: web3.utils.toHex(21000), 

    gasPrice: web3.utils.toHex(web3.utils.toWei('10', 'gwei'))

}

const tx = new Tx(txObject)

Thank you for your help

Take care

Pierre