If successful in taking over the club, McInnes will be appointed chairman.
"Portsmouth Football Club, outside of my family, has been the most important thing in my life for the past 51 years," McInnes told BBC Sport.
Portsmouth fan wants to save club
"The dawn of realisation hit me the other day that we could well be in a situation that, in just over a week, this club could no longer exist after 110 years. With no football the city loses its heartbeat."
The PST is vying for control of Pompey with former owner Balram Chainrai, who has £17.5m secured credit against the club.
On Thursday, the PST revealed it had offered Chainrai £2.75m to effectively walk away from the club, with ownership of Fratton Park part of the deal.
"I can't imagine this club not being there next season and I will do whatever it takes to make sure they are," McInnes added.
The other three high-net-worth backers of the club are venture capitalists Ken Terry and Chris Moth, who, like McInnes, are life-long supporters of Pompey.
There is one other confirmed investor who is currently away on holiday and because of that cannot be named.
McInnes, who made his money in electronics, says there are other interested investors who could subsequently pledge six-figure sums.
The 61-year-old also revealed that one major backer has also emerged in the past 24 hours.
Who is Iain McInnes?
Born 1951, Paulsgrove, Portsmouth
First job: Furniture designer at White & Newton
Joins electronics company Kenwood, aged 19. Sacked six years later
Starts electronic component distribution company and manufacturing company
Sells businesses in 1995 with collective turnover of £10.5m
First approached by Portsmouth for financial assistance in 1996
Turns downs opportunity to become a director of the club
Comes out of retirement. Currently runs various electronic companies
Current turnover of companies is £18m, with 300 people employed
"I hate the term high-net-worth individual as I was born in Paulsgrove and what that term means we have slightly more funds, so we can put in slightly more money," he said.
"But there might be more than four high-net-worth individuals any time soon. There is also the news that a major backer, who has come from the left wing as it were, wants to meet with the Trust, so we could well have more money."
McInnes says he is relishing the chance to help save the club he loves but admits time is running out.
He has urged administrator Trevor Birch and Chainrai to meet the PST as soon as possible to thrash out a deal.
He said: "My message to Chainrai is we will meet any time and place, and we have far more chance of saving the club if we work together rather than apart.
"Things have to have moved on by the end of the week as time is running out."
Birch issued a statement to BBC Sport on Thursday saying he welcomed news of the PST's bid and promised to work with it to "find a solution that will satisfy everyone".
"We welcome the Trust's announcement and will carefully study the details of the proposal," said the statement.
"Now that we all know more about the Trust's plans, we will work with them and Portpin (Chainrai's company) to see if we can find a solution that will satisfy everyone involved, including the unsecured creditors and the Football League.
"As court-appointed officials, it is our duty to explore all of the available options. In the meantime we will continue to talk to the remaining players to secure the compromise agreements."
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